Container Soils - Water Movement & Retention XII

November 3, 2010

I first posted this thread back in March of '05. Eleven times previous, it has reached the maximum number of posts GW allows to a single thread, which is much more attention than I ever imagined it would garner. I have reposted it, in no small part because it has been great fun, and a wonderful catalyst in the forging of new friendships and in increasing my list of acquaintances with similar growing interests. The forum and email exchanges that stem so often from the subject are, in themselves, enough to make me hope the subject continues to pique interest, and the exchanges provide helpful information. Most of the motivation for posting this thread another time comes from the participants' reinforcement of the idea that some of the information provided in good-spirited collective exchange will make/has made some degree of difference in the quality of many readers' growing experience.

I'll provide links to some of the more recent of the previous eleven threads and nearly 1,800 posts at the end of what I have written - in case you have interest in reviewing them. Thank you for taking the time to examine this topic - I hope that any/all who read it take at least something interesting and helpful from it. I know it's long; my hope is that you find it worth the read.

Container Soils - Water Movement and Retentioncolor>size>

A Discussion About Soilscolor>size>

As container gardeners, our first priority should be to insure the soils we use are adequately aerated for the life of the planting, or in the case of perennial material (trees, shrubs, garden perennials), from repot to repot. Soil aeration/drainage is the most important consideration in any container planting. Soils are the foundation that all container plantings are built on, and aeration is the very cornerstone of that foundation. Since aeration and drainage are inversely linked to soil particle size, it makes good sense to try to find and use soils or primary components with particles larger than peat/compost/coir. Durability and stability of soil components so they contribute to the retention of soil structure for extended periods is also extremely important. Pine and some other types of conifer bark fit the bill nicely, but I'll talk more about various components later.

What I will write also hits pretty hard against the futility in using a drainage layer of coarse materials as an attempt to improve drainage. It just doesn't work. All it does is reduce the total volume of soil available for root colonization. A wick can be employed to remove water from the saturated layer of soil at the container bottom, but a drainage layer is not effective. A wick can be made to work in reverse of the self-watering pots widely being discussed on this forum now.

Since there are many questions about soils appropriate for use in containers, I'll post basic mix recipes later, in case any would like to try the soil. It will follow the Water Movement information.

Consider this if you will:

Soil fills only a few needs in container culture. Among them are: Anchorage - A place for roots to extend, securing the plant and preventing it from toppling. Nutrient Retention - It must retain enough nutrients in available form to sustain plant systems. Gas Exchange - It must be sufficiently porous to allow air to move through the root system and by-product gasses to escape. Water - It must retain water enough in liquid and/or vapor form to sustain plants between waterings. Most plants can be grown without soil as long as we can provide air, nutrients, and water, (witness hydroponics). Here, I will concentrate primarily on the movement of water in soil(s).

There are two forces that cause water to move through soil - one is gravity, the other capillary action. Gravity needs little explanation, but for this writing I would like to note: Gravitational flow potential (GFP) is greater for water at the top of the container than it is for water at the bottom. I'll return to that later.

Capillarity is a function of the natural forces of adhesion and cohesion. Adhesion is water's tendency to stick to solid objects like soil particles and the sides of the pot. Cohesion is the tendency for water to stick to itself. Cohesion is why we often find water in droplet form - because cohesion is at times stronger than adhesion; in other words, water's bond to itself can be stronger than the bond to the object it might be in contact with; in this condition it forms a drop. Capillary action is in evidence when we dip a paper towel in water. The water will soak into the towel and rise several inches above the surface of the water. It will not drain back into the source, and it will stop rising when the GFP equals the capillary attraction of the fibers in the paper.

There will be a naturally occurring "perched water table" (PWT) in containers when soil particulate size is under about .125 (1/8) inch. This is water that occupies a layer of soil that is always saturated & will not drain from the portion of the pot it occupies. It can evaporate or be used by the plant, but physical forces will not allow it to drain. It is there because the capillary pull of the soil at some point will surpass the GFP; therefore, the water does not drain, it is said to be 'perched'. The smaller the size of the particles in a soil, the greater the height of the PWT. This water can be tightly held in heavy (comprised of small particles) soils and 'perch' (think of a bird on a perch) just above the container bottom where it will not drain; or, it can perch in a layer of heavy soil on top of a coarse drainage layer, where it will not drain.

Imagine that we have five cylinders of varying heights, shapes, and diameters, each with drain holes, and we fill them all with the same soil mix, then saturate the soil. The PWT will be exactly the same height in each container. This saturated area of the container is where roots initially seldom penetrate & where root problems frequently begin due to a lack of aeration. Water and nutrient uptake are also compromised by lack of air in the root zone. Keeping in mind the fact that the PWT height is dependent on soil particle size and has nothing to do with height or shape of the container, we can draw the conclusion that: Tall growing containers will always have a higher percentage of unsaturated soil than squat containers when using the same soil mix. The reason: The level of the PWT will be the same in each container, with the taller container providing more usable, air holding soil above the PWT. From this, we could make a good case that taller containers are easier to grow in.

A given volume of large soil particles has less overall surface area when compared to the same volume of small particles and therefore less overall adhesive attraction to water. So, in soils with large particles, GFP more readily overcomes capillary attraction. They drain better. We all know this, but the reason, often unclear, is that the height of the PWT is lower in coarse soils than in fine soils. The key to good drainage is size and uniformity of soil particles. Mixing large particles with small is often very ineffective because the smaller particles fit between the large, increasing surface area which increases the capillary attraction and thus the water holding potential. An illustrative question: How much perlite do we need to add to pudding to make it drain well?

We have seen that adding a coarse drainage layer at the container bottom does not improve drainage. It does though, reduce the volume of soil required to fill a container, making the container lighter. When we employ a drainage layer in an attempt to improve drainage, what we are actually doing is moving the level of the PWT higher in the pot. This simply reduces the volume of soil available for roots to colonize. Containers with uniform soil particle size from top of container to bottom will yield better and more uniform drainage and have a lower PWT than containers using the same soil with drainage layers.

The coarser the drainage layer, the more detrimental to drainage it is because water is more (for lack of a better scientific word) reluctant to make the downward transition because the capillary pull of the soil above the drainage layer is stronger than the GFP. The reason for this is there is far more surface area on soil particles for water to be attracted to in the soil above the drainage layer than there is in the drainage layer, so the water perches. I know this goes against what most have thought to be true, but the principle is scientifically sound, and experiments have shown it as so. Many nurserymen employ the pot-in-pot or the pot-in-trench method of growing to capitalize on the science.

If you discover you need to increase drainage, you can simply insert an absorbent wick into a drainage hole & allow it to extend from the saturated soil in the container to a few inches below the bottom of the pot, or allow it to contact soil below the container where the earth acts as a giant wick and will absorb all or most of the perched water in the container, in most cases. Eliminating the PWT has much the same effect as providing your plants much more soil to grow in, as well as allowing more, much needed air in the root zone.

In simple terms: Plants that expire because of drainage problems either die of thirst because the roots have rotted and can no longer take up water, or they starve/"suffocate" because there is insufficient air at the root zone to insure normal water/nutrient uptake and root function.

Bark fines of fir, hemlock or pine, are excellent as the primary component of your soils. The lignin contained in bark keeps it rigid and the rigidity provides air-holding pockets in the root zone far longer than peat or compost mixes that too quickly break down to a soup-like consistency. Conifer bark also contains suberin, a lipid sometimes referred to as nature's preservative. Suberin, more scarce as a presence in sapwood products and hardwood bark, dramatically slows the decomposition of conifer bark-based soils. It contains highly varied hydrocarbon chains and the microorganisms that turn peat to soup have great difficulty cleaving these chains.

To confirm the existence of the PWT and how effective a wick is at removing it, try this experiment: Fill a soft drink cup nearly full of garden soil. Add enough water to fill to the top, being sure all soil is saturated. Punch a drain hole in the bottom of the cup and allow the water to drain. When drainage has stopped, insert a wick into the drain hole . Take note of how much additional water drains. Even touching the soil with a toothpick through the drain hole will cause substantial additional water to drain. The water that drains is water that occupied the PWT. A greatly simplified explanation of what occurs is: The wick or toothpick "fools" the water into thinking the pot is deeper than it is, so water begins to move downward seeking the "new" bottom of the pot, pulling the rest of the water in the PWT along with it. If there is interest, there are other simple and interesting experiments you can perform to confirm the existence of a PWT in container soils. I can expand later in the thread.

I always remain cognizant of these physical principles whenever I build a soil. I have not used a commercially prepared soil in many years, preferring to build a soil or amend one of my 2 basic mixes to suit individual plantings. I keep many ingredients at the ready for building soils, but the basic building process usually starts with conifer bark and perlite. Sphagnum peat plays a secondary role in my container soils because it breaks down too quickly to suit me, and when it does, it impedes drainage and reduces aeration. Size matters. Partially composted conifer bark fines (pine is easiest to find and least expensive) works best in the following recipes, followed by uncomposted bark in the Note that there is no sand or compost in the soils I use. Sand, as most of you think of it, can improve drainage in some cases, but it reduces aeration by filling valuable macro-pores in soils. Unless sand particle size is fairly uniform and/or larger than about BB size, I leave it out of soils. Compost is too fine and unstable for me to consider using in soils. The small amount of micro-nutrients it supplies can easily be delivered by one or more of a number of chemical or organic sources that do not detract from drainage/aeration.

My Basic Soils ....

5 parts pine bark fines (partially composted fines are best)

1 part sphagnum peat (not reed or sedge peat please)

1-2 parts perlite

garden lime (or gypsum in some cases)

controlled release fertilizer (if preferred)

micro-nutrient powder, other source of micro-nutrients, or fertilizer with all nutrients - including minors

Big batch:

2-3 cu ft pine bark fines

5 gallons peat

5 gallons perlite

2 cups dolomitic (garden) lime (or gypsum in some cases)

2 cups CRF (if preferred)

1/2 cup micro-nutrient powder (or other source of the minors - provided in some fertilizers)

Small batch:

3 gallons pine bark

1/2 gallon peat

1/2 gallon perlite

4 tbsp lime (or gypsum in some cases)

1/4 cup CRF (if preferred)

micro-nutrient powder (or other source of the minors)

I have seen advice that some highly organic (practically speaking - almost all container soils are highly organic) container soils are productive for up to 5 years or more. I disagree and will explain why if there is interest. Even if you were to substitute fir bark for pine bark in this recipe (and this recipe will long outlast any peat based soil) you should only expect a maximum of two to three years life before a repot is in order. Usually perennials, including trees (they're perennials too) should be repotted more frequently to insure vigor closer to their genetic potential. If a soil is desired that will retain structure for long periods, we need to look more to inorganic components. Some examples are crushed granite, fine stone, coarse sand (see above - usually no smaller than BB size in containers, please), Haydite, lava rock (pumice), Turface, calcined DE, and others.

For long term (especially woody) plantings and houseplants, I use a superb soil that is extremely durable and structurally sound. The basic mix is equal parts of pine bark, Turface, and crushed granite.

1 part uncomposted screened pine or fir bark (1/8-1/4")

1 part screened Turface

1 part crushed Gran-I-Grit (grower size) or #2 cherrystone

1 Tbsp gypsum per gallon of soil

CRF (if desired)

Source of micro-nutrients or use a fertilizer that contains all essentials

I use 1/8 -1/4 tsp Epsom salts per gallon of fertilizer solution when I fertilize (check your fertilizer - if it is soluble, it is probable it does not contain Ca or Mg.

If there is interest, you'll find some of the more recent continuations of the thread at the links below:

Post XI

Post X

Post IX


Post VII

If you feel you were benefited by having read this offering, you might also find this thread about Fertilizing Containerized Plants helpful, as well.

As always - best luck.


Comments (150)

  • Woebegonia

    There seems to be a substitution of coconut fiber/coir whatever it is called for sphagnum in pre-mixed products, I don't think I like the idea. I suppose you can cut back on adding lime. Which would you prefer if you had the choice?

  • meyermike_1micha

    I too am so vey happy for you!!! Look at you all go everyone!

    I knew that you would all get excited about your journeys as I did, and get the help you needed too! That is why I am always referring many here.

    Laura, I am very proud of you sticking with your plan and doing what ever it took to find what you needed!
    I love the way your plumeria look. Oh they look so nice. I too have to set a line production of all mine into the gritty mix with bigger containers. Mine too are all resting and can't come out until I can put them into my pop up and let the temps get as hot as they want in there.

    Al, as ALWAYS, I too appreciate all you have done for me, and for my many friends! Thank you:-0))))

    Please, watch for Jessica, since she too would love to experience all the excitement around here...

    Hi Jerry, I never met, and anyone else I might of missed including those dear to me. Gotta run.


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    The little gnatties like to feast on dead and decaying plant matter, and love it moist. Yep that 'covermoss' is prone to sheltering and keeping a colony of the little buggers. I clean up my plants and keep them 'clean' all the time (old leaves removed and no debris left in the top of the pot) and that helps some on not ever seeing them. I housesit for someone and she always comments when she comes back that I have cleaned up and cleaned out every one of her plants... she always has problems with various disease issues and if she would just CLEAN UP she'd have a lot less problems. Also, remove the trash immediately... she would have this big rolling garbage cans and wouldn't empty them for months on end. I remove my greenhouse trash when I'm through and ready to go back to the house. If I run into something like mealy bugs, that gets carried out immediately! (a local nursery has issues with it, anything you bring home from there has to be isolated and cleaned up) Between that friend and myself we have fought this war for fourth winter. I am now 'clean' and she is still having issues (I have also tossed a few plants to stop the infestation and she won't... so she keeps breeding more). If you get mealy bugs in your house and your houseplants; second worse is spider mites; you will have a long and hard one to get that one cleaned up. First picture, if you remove the few leaves you find and remove them from the area then wash up, you will probably get it right there. Missing one fleck, you will find first or second picture in 1-4 weeks. I don't spray because a lot of sprays they seemed to ignore; I killed the plant along with the bugs; and in my greenhouse I am doing semi-aquaculture and sprays/chemicals are not a good thing around the fish. I can tell you insecticidal soap has never seemed to work even if I pretty much drowned the plant in it and it usually has killed the plant at that level. I do 'clean up plants' and 'toss badly infected plants pot and all' ... at times I can find a part of the plant that is almost clean, hand clean a few small flecks off, and put it into an isolation cutting cup-and toss the main plant. In a few weeks either it has gone rampantly infected in which case I toss the whole cup, or it's clean yet and rooted so I can pot it up. I've cried over some plants I've tossed, but. Upper Left, Usually you will see just one or two flecks, underside of leaves, near a leaf to stem join, by the time you see this much you'll be well into the battle. Size of very small salt grains if that big. Upper Right, Well engaged, this is trim this off and remove it; or if the whole plant looks like this it's going to be tossed. Lower Left, if you see these, about the size of two to three salt grains glued together in a string, you have major problems Lower RightMature mealys, about 1/8 inch long, (3mm), and I usually see the matures as a light gray like this. The smaller is white, the mature is this grey, and they are highly detailed. Start checking all the plants around this one and be very serious about check EVERY bit. All it takes is one tiny white cottony looking fleck....
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  • PRO

    Woebegonia (I like that name - very clever) - I don't like coir as a significant fraction of any mix. I wrote this a while ago & I think it is a good explanation as to why I prefer peat over coir and conifer bark over CHCs:

    Sphagnum peat and coir have nearly identical water retention curves. They both retain about 90-95% of their volume in water at saturation and release it over approximately the same curve until they both lock water up so tightly it's unavailable for plant uptake at about 30-33% saturation. Coir actually has less loft than sphagnum peat, and therefore, less aeration. Because of this propensity, coir should be used in mixes at lower %s than peat. Because of the tendency to compact, in the greenhouse industry, coir is primarily used in containers in sub-irrigation (bottom-watering) situations. Many sources produce coir that is high in soluble salts, so this can also be an issue.

    Using coir as the primary component of container media virtually eliminates lime or dolomitic lime as a possible Ca source because of coir's high pH (6+). Gypsum should be used as a Ca source, which eliminates coir's low S content. All coir products are very high in K, very low in Ca, and have a potentially high Mn content, which can interfere with the uptake of Fe.
    I haven't tested coir thoroughly, but I have done some testing of CHCs (coconut husk chips) with some loose controls in place. After very thoroughly leaching and rinsing the chips, I made a 5:1:1 soil of pine bark:peat:perlite (which I know to be very productive) and a 5:1:1 mix of CHCs:peat:perlite. I planted 6 cuttings of snapdragon and 6 cuttings of Coleus (each from the same plant to help reduce genetic influences) in containers (same size/shape) of the different soils. I added dolomitic lime to the bark soil and gypsum to the CHC soil. After the cuttings struck, I eliminated all but the three strongest in each of the 4 containers. I watered each container with a weak solution of MG 12-4-8 with STEM added at each watering, and watered on an 'as needed basis', not on a schedule. The only difference in the fertilizer regimen was the fact that I included a small amount of MgSO4 (Epsom salts) to provide MG (the dolomitic lime in the bark soil contained the MG, while the gypsum (CaSO4) in the CHC soil did not. This difference was necessary because or the high pH of CHCs and coir.) for the CHC soil.

    The results were startling. In both cases, the cuttings grown in the CHC's exhibited only about 1/2 the biomass at summers end as the plants in the bark mix.

    I just find it very difficult for a solid case to be made (besides "It works for me") for the use of coir or CHC's. They're more expensive and more difficult to use effectively. The fact that some believe peat is in short supply (no where near true, btw) is easily offset by the effect of the carbon footprint of coir in its trek to the US from Sri Lanka or other exotic locales.
    That's the view from here. YMMV


  • jodik_gw

    I second Al's view... I've had personal experience with cococoir/peat, and I'll never use it again! It's way too quick to compact, and even the pre-rinsed coir holds an amount of harmful saline. It also grew the strangest molds I've ever seen, and held moisture for way too long a span of time. I lost a few amaryllids to rot using the coco peat.

    After having used the Gritty Mix, I can say with all honesty that I much prefer the fir bark/perlite/turface/granite chip medium mix for my indoor plants. It puts me in control of moisture and nutrition... and it's not a "water in sips" or a waiting game while the medium dries out from total saturation, drowning roots!

    I have yet to use the bark/peat/perlite mix for my outdoor containers, but I trust Al's experiences and I know that it'll net me the good results I'm after.

  • Woebegonia

    Thank you, now I know what I am up against and I can think things over.

  • ligreenthumb

    Dear all,

    Been a reader for a while by new to the posting. Sorry for the long post here. Saw Laura's plumerias and decided to poll the group.

    I'm very intrigued by the 5:1:1 and "gritty" and was trying to determine how best to use each. I'd have a few active discussions with fellow co-workers about this too, and I'd appreciate the feedback from you fine folks here.

    My indoor plants vary greatly from plumeria, to various cacti/succulents (barrel cactus, Sempervivum, Haworthia), african violets, holiday cactus (Schlumbergera and Rhipsalidopsis), Alpinia, and Curcuma? If yes, what do you think would be best?

    Has anyone had success with orchids, esp. laeliocattleya, bletilla, or calanthe? A close friend has who has grown orchids for years thinks this mix may not be ideal.

    Also, has anyone tried bone meal instead of the lime/gypsum?

    Thanks for the help.

  • greenman28 NorCal 7b/8a


    I grow cacti and succulents such as Jades and Euphorbia and Desert Rose in the Gritty Mix.

    Junge Cacti, such as Christmas Cactus, I grow in a mix that is very similar to the 5-1-1.
    I have African Violets, Orchid, and Hoyas growing in the 5-1-1, as well.

    I would not recommend bone meal as a substitute for lime/gypsum.


  • PRO

    The soils are essentially interchangeable, but the guideline I use runs to how long I expect that individual planting to go between repots. By 'repot', I mean a full repot, which includes removing old soil and reducing the root mass of most plants, sometimes dividing certain plantings.

    If a planting is seasonal, like veggies and mixed floral display plantings of plants we treat as annuals, I usually always opt for the 5:1:1 mix. It's less expensive and there is very little concern for breakdown in a years time. Often, I'll extend the interval of some plantings in the 5:1:1 mix to 2 years. I impose the 2 year limit on myself not because the soil will only remain serviceable for two years, it retains its structure FAR longer than other soils based on peat/compost/coir and other fine organic particulates, it's just that I'm fussy about my soils AND the intervals between repots. Plant growth and vitality begin to be negatively affected at about the point where the soil/root mass can be lifted from the container intact. If the planting is allowed to become additionally root-bound beyond that point, the planting has to have the root condition corrected by a full repot or it will be permanently affected.

    Everything I grow long term goes in the gritty mix. All my houseplants, C&S, and woody material I'm growing on for bonsai are repotted into the gritty mix at the first opportunity. Properly made, the gritty mix holds good amounts of water w/o holding perched water, which is the water in soils that kills roots, causing the cyclic death and regeneration of fine roots after soils are saturated. The gritty mix is designed to eliminate this cycle that saps energy as roots that are paid for die and the plant is charged with paying for roots being newly generated from the plant's energy reserves, reserves that might have gone into producing more fruit, blooms, foliage, or simply increasing biomass.

    For all intents and purposes, bone meal breaks down so slowly in containers it has no effect on pH or nutrient levels. I tend to me minimalistic in what I include in my soils aimed at supplying nutrients, adding nothing that might upset the balance of the 3:1:2 ratio fertilizers I almost always use. As an example, if you are using Foliage-Pro 9-3-6, it supplies all 12 essential nutrients in as close to the exact proportions that plants use that you're likely to find in a commercial product. Anything else you add, whether it's extra Fe, P, N ..... is going to be an excess. Liebig's Law of the Minimum recognizes an excess of any potential limiting factor as as potentially limiting as a deficiency.

    It makes the best sense to use dolomite, which supplies both Ca and Mg in a favorable ratio to supply these elements and adjust the pH of the 5:1:1 mix. The gritty mix comes in at a higher pH than the 5:1:1 mix, so we generally only add gypsum as a Ca source when our soluble fertilizer lacks Ca. This usually requires the addition of a little Epsom salts in the fertilizer solution each time you fertilize. More on that if necessary once your course is plotted.


  • ligreenthumb

    Thanks for your comments Josh. Wondering how often you re-pot your plants (see also Al's subsequent post). In the case of the Junge Cacti, how do you deal with container size since I thought many of these types of plants prefer a more restricted environment(spacial crowding as in their natural habitat)?

  • ligreenthumb


    Thanks for your message. As a scientist (but not botanist) I appreciate your methodologies and thoughtful approach. I do have a few follow-up questions that I hope you don't mind addressing.

    I have seen from posts here that there are different fertilizers that could be used. My aim is to try and naturally apply nutrients/minerals through supplementation that reflect a plant's natural habitat while trying to have such nutrients exist in the best form possible. As an analogy, complex carbohydrates provide a more sustained nutrient level to animals than do simple sugars. How can I achieve this when moving to the "gritty" or 5:1:1? Obviously, the presence of compost is not such a good idea in containers, so how do I best mimic this intent?

    Can you provide any measured "soil" pH for either the gritty or 5:1:1. If you need a more acidic environment for a particular plant, would you use garden sulfur (and if so, how), or do you add something in liquid form during fertilizing/watering.

    Thanks again.

  • jodik_gw

    I grow a few orchids in the Gritty Mix, mainly Dendrobiums... and the majority of my plant collection consists of bulbs... amaryllids, mainly.

    I vary the ingredients and the ratios used depending on plant type, placement, and other variables. The Dens are in a mix consisting of more bark than turface or granite... the bulbs are in a fairly equal mix of all ingredients... I don't want to have to re-pot often, so the gritty mix works great for my uses.

    Since container growing varies so differently from growing in the ground, I stick with a more inorganic approach, both in medium and in nutrition. I use nothing more than Miracle Gro liquid with the addition of STEM micro-nutrients, to ensure my plants get what they require.

    I think all plants would spread out their roots comfortably if they could... and potting them tightly only puts them into stress, whereby they bloom or offset in anticipation of pending death due to those stresses. So, the fallacy that being potbound is preferable to some plants... I just don't buy. The beauty of a faster draining medium is it allows larger pots to be used because there's no or minimal perched water. The medium doesn't remain saturated, thus drowning or suffocating important root structure.

  • PRO

    Jodi is right - from a physiological perspective, no plant likes tight roots - if they did, Mother Nature would have arranged for their roots to grow in tight little geometric shapes immediately under the stems. You can read more about why plants don't prefer to be rootbound if you follow the embedded link. You can use the added stress that rootbound conditions create to bend the plant to your will in some cases, but it's important to realize that from the plant's perspective, any stress is a negative and impacts growth/vitality.

    Even though there is little difference between the way our body actually handles simple vs complex carbohydrates (other than speed), I can probably take the nomer of 'complex carbohydrate' to mean 'digestible saccharide' that exists in whole foods and that also includes vitamins, minerals, fiber .... contrasting with the processed carbohydrates we often refer to as 'empty calories'. Am I on the right track, here?

    I think our goals are divergent, but let me propose something after I make a few observations. Containers are radically different than gardens. What works well in gardens is often a disaster in a container, For example, using topsoil in containers can usually be relied upon to produce very poor results. Mixing compost into the topsoil as a nutrient source or to improve soil structure is usually a disaster. Micro-organism populations are reliably boom/or bust in containers, so delivery of nutrients is erratic and unreliable. Using organic soil amendments as a nutrient source, like various meals, often has a negative impact on soil structure, and usually wondering what we've applied and when it will be available.

    Soluble fertilizers, on the other hand, can be applied as often as you prefer. You can maintain a very precise level of nutrients in the soil, and control the RATIO of nutrients, one to the other, at all times. This is of great benefit if your goal is plant vitality or best growth. In gardens, we can almost get away entirely with only 'feeding the soil', but in container culture, we actually benefit from NOT feeding the soil - from NOT adding things that break down quickly, promoting huge populations of microorganisms that also break down the soil particles, destroying the soils structure, which is key in container culture.

    I achieve a steady and even supply of nutrients in the winter by fertilizing all the indoor plants with a low dose every time I water. It works exceptionally well. I would maintain this same regimen in summer if I had the time, but with more than 300 containers to tend each year, I would only be able to take the time to fertilize every time I water if I used an injection system. Instead, I usually fertilize weekly by hand at about 1/2 the recommended dose, depending on temperatures. If it's above 85* or below 55*, I usually withhold fertilizer until the weather changes. This would be especially true if using urea/ammonia-based fertilizers.

    Finally - the only realistic way for container gardeners to manage pH is by managing the pH of their irrigation/fertigation water. Vinegar or citric acid can be added to your water to neutralize alkalinity and bring the pH down to a target level. Once the volume required is established, adding the same amount of the acidifying compound to the water each time you irrigate/fertigate allows you to maintain pH within your desired range.


  • greenman28 NorCal 7b/8a

    Al is right on! Solid information flows from his fingertips ;-)

    Howdy, Greenthumb, I usually re-pot after one or two years...or sooner if the roots
    have totally colonized the mix. The Jungle Cacti grow in any size container that I choose,
    and they thrive! I have them in large terracotta, and I have them in moderately sized plastic, as well.
    With bark-based mix, I root cuttings in the container in which I intend to grow them.

    As Jodi and Al explained, plants don't like or prefer restricted roots.


  • ligreenthumb

    Dear all,

    Thanks for all of your valuable input. I'm intrigued by the comments posted, and have more questions.

    Jodik, would you be willing to provide me with some idea of the proportions used with your orchid care, or direct me where I may start? From the various posts and threads, it seems the gritty mix is forgiving, but I'd appreciate the insights regardless.

    Obviously there will be a learning curve to watering with either the gritty or 5:1:1, or any modification for that matter. How essential is the wick to the newcomer in learning when to water, and when not? If you don't use a wick, and as an example, a plant sits in full sun outdoors in the NE, what should one be looking for? It seems that wet to the touch doesn't work.

    Also, in thinking about bulbs, or other plants that require drier conditions, or that can be forced (like amaryllis), how does one adapt the watering conditions? How do you deal with rest periods, such as the case for a wintering plumeria?

    In response to Al's message, there is a clear difference between the container and the garden. I appreciate the insights about nutrient administration. I know there are lots of myths that need to be debunked before I am truly successful. Maybe I should start each post with a disclaimer about my gardening knowledge being only a few truths and many myths.

    I suspect that within Al's comment regarding nutrient consistency and availability in containers, he touched on a principle that seems a crucial foundation for a successful outcome. I can speak from my experience regarding the irregular results I've observed using more of a "soil." I've been concerned about drainage and aeration but until more recently, haven't started to appreciate the troublesome conditions I have been creating.

    Another personal myth I've been lead to believe and that I now need to break is that gardeners who use defined soluble fertilizers are not taking short-cuts in not "feeding the soil" but may in fact be thinking about consistent nutrient/mineral delivery, ESPECIALLY when working with containers. I have always liked the concepts of robustness and repeatability, and it seems all of you have done sufficient experiments already to help lead me to believe otherwise.

    I'd like to start a new thread about nutrients/feeding/fertilizer? What does everyone think -- sufficient benefit to others? (It's also a bit off topic from water movement, and I'd like to keep the focus for this one.) Obviously I would need lots of help here from you, since you have already done so much of the hard work. :) If not, I can always post again here.

    Again, thanks for your various posts, and wishing you all happy gardening.

  • PRO

    If the gritty mix is properly made, a wick is just insurance for the newbie who can't imagine that the gritty mix holds any water, given the speed with which water flows through the soil. Until they get their mind wrapped around the idea that it holds much more water than they think, the wick can serve as an instant remedy to a heavy watering hand, or as a 'tell' that will indicate when it's ok to water (when the wick is dry where it emerges from the pot).

    Maybe Jodi will include more insight when she talks about her bulbs, but I don't treat resting plants in the gritty mix any differently than I would treat them in another mix - other than to perhaps water a little more frequently. The highly porous soil does dry down faster than heavier soils.

    "I can speak from my experience regarding the irregular results I've observed using more of a "soil." I've been concerned about drainage and aeration but until more recently, haven't started to appreciate the troublesome conditions I have been creating."

    I'll say 'good', but only from the perspective that it leaves you open to considering alternatives. I've never suggested that the free-draining soils I and many others are using are for everyone - though they CAN be, for anyone willing to go to the effort of gathering the materials & mixing the soils. Once sources are found, the largest drawback is the increased watering frequency. These soils definitely offer greater opportunity for your plants to grow as near as possible to their genetic potential, defining the question as, "Do I want to sacrifice a little convenience for greater opportunity for better plant performance?" Since I'm BEING fair, I don't feel bashful about saying that the soils offer much greater latitude and margin for error in the areas of reducing over-watering and decreasing the likelihood of fertilizing mistakes.

    I don't look at soluble fertilizers as a convenient way to avoid "all the things you need to do to have a healthy garden'. On the contrary - I think that for the results oriented, not only are soluble fertilizers are the most efficacious way to get nutrients to plants, allowing the grower complete control over exactly what his plants get and exactly when they get it, but we can take advantage of a stroke of luck in that it also happens to be the easiest way, by far. It is really only when ideology or politics comes to play that we hear anything negative about soluble fertilizers for container culture. To be sure, I strongly believe in feeding the soil in my gardens & beds, fertilizing minimally if at all and relying primarily on compost and mulch to build soil health and nutrient content; but I've found that if I leave that concept in the garden and not try to export it from there to my containers, I'm much better off.

    Start a new thread if you wish. I don't know if you read it or not, but this discussion about fertilizer strategies for containers should answer a lot of your questions. Feel free to piggyback on that thread, or start your own if you feel that would serve your purpose better.

    Thank you for the kind words. I'll look forward to helping and/or offering insight where I can.


  • jodik_gw

    Sure, Greenthumb... let me preface by saying, while I consider myself a novice orchid grower, I've actually been dabbling in growing one plant type or another since I was quite young. If I had met Al 40 years ago, I'd be so much further along in my success and enjoyment of gardening, both indoors and outdoors!

    Anyway, I find it important to know what each ingredient brings to the mix... as example, turface brings a certain amount of water retention, granite is inert and simply adds to the overall volume of larger particulate, creating the desired air pockets, etc... and since bark is widely used for orchid growing, it seemed logical to make it the main ingredient in my orchid medium. It, too, holds a certain amount of moisture, but I'd say not as much as turface, and by its very shape would be perfect for orchid roots, which behave as they do.

    However, since my home environment is overly dry, lacking humidity to a very big extent, I want some moisture retention. So, I use a little turface, and I use the fir bark in larger quantities than the granite chips, turface and perlite. I keep the fir bark the majority ingredient by volume for orchids. How much, exactly? I don't really know... I eyeball it as I mix. I wish I could be precise, but I just can't.

    Most of my container growing occurs indoors, and most is in pots between 2" and say, 12" or a bit larger. For my orchids, I try to use opaque or clear pots so I can see the roots and condensation inside the pot. This helps me know when moisture levels are high or low. The skewer method also helps.

    Because I grow most of my indoor plants in smaller containers, I only need to mix small batches of medium at any one time. You'll get a feel for how much of each ingredient to add to a batch, depending upon variables such as moisture retention, the plant type and its requirements, your individual environment, where you place the container, sun or shade, etc...

    There is a learning curve to the gritty mix, but it's not as difficult as a few people would have you believe. In a given situation, you may have to water more often... and you may not. It greatly depends upon the plant, its requirements, your climate and environment, etc... all the usual variables. Plants should be watered as they need moisture, and not weekly or bi-weekly or on any set schedule, as some unknowing growers are wont to do.

    Where do you start with ingredients? Right here, in this very thread, with the basic recipes. Think about the concept of the mix, what each ingredient offers, their relationship to each other within the mix, which recipe you'll be using... most growers, it seems, use the 511 for outdoor use and the gritty mix for indoor use, or the 511 for shorter term plantings and the gritty for longer term plantings... the plant type you're growing, and the environment in which you'll be growing in.

    It's wise to begin with an easy plant and the basic recipe, and learn the ins and outs of caring for it in the gritty mix or the 511, and then move on to other plant types once you're familiar with it. I began by potting a Sanseveria and a few Hippeastrum bulbs in it, and once I was comfortable with its care, moved on to re-potting my orchids and my rarer Amaryllids.

    The first myth we have to get past is that there's such a thing as a green thumb... that gardening is luck and you can either grow or you can't. That's nonsense. A green thumb is nothing more than knowledge. A successful grower knows that the application of knowledge brings success, that learning the basic science of how plants grow and what they need... learning the "how" and the "why" of it all will net us the best results.

    The second myth is that all growing is the same. Not true. Growing within the confines of a container is vastly different than growing in the ground. The abridged version is that outdoors, in the garden, Mother Nature provides a balance of good and bad, and a vast army of living creatures and micro-organisms that work in diligent harmony to decompose, to break down matter into usable nutrition for plants. This same army and balance is nigh impossible to maintain within the small space of a container, and the balance is all too quickly thrown off, most often leading to plant death and disaster.

    I'll add a third myth... that the commercial industry works for gardeners. Not true. Like any other industry, its main objective is profit. If they provided us with the mediums plants preferred and the knowledge to grow all the plants sold, they'd quickly be out of business. Some plants can live and thrive for generations with proper care. Take the art of bonsai, as example... some of those trees are hundreds of years old! No repeat business there!

    Just remember that knowledge holds the keys to your success, and through that success, your enjoyment of growing... and you'll do just fine! What's more important to you? Growing to your, and the plants' potential? Or convenience?

    I hope this gives you some things to think about... I read through the article contained at the beginning of this thread several times before it all came together for me, and I understood what it was I had been doing wrong all these years. I even copied and pasted the article, along with the recipes for the mixes, to my desktop so I could refer to it from time to time. It's really helped me a lot.

    Al writes in such a wonderfully simple style, explaining everything in detail from a layman's perspective... so anyone can grasp the basics of how plants grow and what they need, and their relationship to soils and water, and how it all behaves together in a container environment.

    Sorry to have written such a book... but I type as I think, and I didn't want to forget anything. :-) Even so, I'm sure I have. Oh, and as for feeding my plants, I do so using an all-purpose liquid plant food, and adding micro-nutrients to ensure good health. I dilute the liquid to about 1/4 or less of the recommended strength, and I water with it every time my plants need watering... about 3 out of 4 times, actually... and on the 4th time, I flush with clear water to ensure there's no buildup of salts within the medium.

    The beauty of the larger particled, grittier mixes is that there's a much wider margin for watering error, and YOU are in complete control of moisture, nutrition, flushing, etc... you control it all. I like that. No guessing. :-)

  • PRO

    Very nicely said, Jodi.

    Thanks for the kind words ..... and thanks for all the effort you put into your post. ;o)


  • ligreenthumb

    Al & Jodi,

    Appreciate your feedback. Certainly is plenty to think through if the plan is to be implemented properly. I've started to make the shopping list, and am still working though volumes I may need, and how to properly screen the material. I know I've seen much of the info here already, but as was just said, I just need to look back over the info again and again till it all clicks.

    I think (perhaps like others?) that I underestimated the unique behavior and properties of the container vs. the outdoor garden. If thought about in the proper context, as many of you here are doing, there can be repeated successes due more to control than chance/luck.

    I'm sure more questions to follow, but for now a thanks to you both. I'd be nice to hear others' success and difficulties too.

    Although I had just found the link (to the fertilizer info) that Al posted a few minutes before I read the post above, thanks for the link!

  • PRO

    Full disclosure: The downside is in the fact that you have to locate sources for suitable ingredients and sometimes screen them (mainly for the gritty mix). For most of us, that inconvenience is offset by the fact that the soils are of such superior quality to most commercial bagged soils and they cost about half as much on a per volume basis as bagged soils. They do require more frequent watering, but from the plant's perspective, that's a good thing. Frequent watering means frequent purging of gasses from the root zone. Additionally, there is a direct correlation between increased drainage/aeration and watering intervals, such that those soils that DO require more frequent watering are virtually assured to offer a better opportunity for plants to flourish.

    Occasionally you'll find someone with a difficulty adapting to one of these mixes. Usually, it will be because substitutions or additions were made to 'improve' the mix before they were even familiar with it, or something wasn't screened - things like that. Occasionally, someone in a very hot/dry climate will find they aren't willing to or can't keep up with watering demands, but by & large the reaction has been overwhelmingly positive.


  • jodik_gw

    Thanks, Al... when you compliment my writing, it means a lot. It means I understand what you've been teaching, and I'm ready to move on to more complicated knowledge! :-)

    We're all only too happy to help, Greenthumb. It gives me pleasure to think that something I've shared can benefit another grower.

    The more you read all the basic info, the more it will click. I can promise you that! For me, it was like a light bulb suddenly lighting up, and I thought, "wow! How could I have not known some of this?!" Most of it is common sense, when you think about it, and very scientifically sound and logical. It all makes perfect sense!

    The next step is implementing what we've learned. I begun by trying to locate the proper ingredients to try the gritty mix... and let me tell you right up front that you won't get much help from the commercial/retail gardening industry! What you will get are some mighty blank looks when you ask about fir bark or turface! Sales clerks will wonder what the heck you could possibly want with such items, and why you'd want to build a soil when bagged dirt is stacked right there. They'll direct you to all kinds of items, most not what you're looking for.

    So, locating what you really want right off the bat may be more difficult than you'd think, but don't give up the ship! Chances are good one of us can direct you to places near you that carry the right ingredients, and there's a thread here in the forum somewhere that addresses locating the various items.

    This is what I use... ZooMed ReptiBark reptile bedding, which is 100% screened, dust free fir bark, available at PetsMart... Manna Pro poultry grit, which is 100% granite chips, though it requires rinsing to remove dust, available at Farm & Fleet or farm oriented stores... coarse perlite, screening required, available anywhere... and turface, screening required, available through the local John Deere dealer.

    This is a photo of the fir bark and granite chip bags I get...

    This is what the ingredients look like... starting left/top and working clockwise... turface, perlite, fir bark, and granite chips...

    The quarter is for size comparison. You'll notice that the ingredients are all comparable in size, with the bark being slightly larger. Some fine orchid barks are smaller, and might suit you better... it depends on the usual variables, and what you are able to locate.

    Once the great group of folks get through with you here, you should be all set up, but in case you can't locate something, other ideas to consider are looking at bonsai growers, orchid growers, mulch companies, garden centers... and NAPA even carries a floor dry product for oil spills that can be substituted for the turface. Some calcined baked clay cat litters might work, as well, though they should be tested to check for durability. But we can cross that bridge if and when we get to it.

    I would recommend Foliage Pro as the fertilizer of choice, though Miracle Gro liquid or other comparable all purpose fertilizer will work just fine. The addition of micro-nutrients may be necessary with some fertilizers.

    Let's see... what am I forgetting? Well, you'll probably want to pick up some wooden skewers... they come 100 to a pack, available at your local grocery store for about a buck. Wicking, I'm not sure about. I don't use it. It's a good idea, especially with larger pots, though. I'm sure Al can tell us what he recommends. Screens for sifting ingredients... I'm not sure where to get those, either... I use insect screen and a colander that has the right mesh size, but I'm sure others can recommend that, too... and screening for the drainage holes in pots, to keep the mix from dribbling out... that can be as simple as the mesh used for needlepoint, available anywhere sewing and craft items are sold.

    So, now you've got a shopping list. Let the treasure hunt begin! And please, feel free to ask any questions you may have... we're all more than happy to help. :-)

  • JerryVentura Jordan

    Hello again,

    My #3 perlite will be in on Tuesday, I have my fir bark, just got back with two bags of Turface MVP, so today will be a day of sifting. I opened a bag of Turface and put a couple scoops in the 1/8 sifter just to see what sifted out, I was suprised how much, I bet 50% went through so I stopped shaken the sifter, seems like a waste, I don't have garden beds to put it in.

    Any thoughts? Maybe I don't need to sift out every little piece, I did notice some of the pics people have posted seem to have some smaller pieces of Turface or perlite in them. Maybe I'm being to precise?

    Just in case someone was going to ask, I'm not using grit, I'm using the perlite instead. I have a back injury and my house plants need to be as light as I can get them so that I can carry them to the sink. My outside container plants and tree's I will probably do a combo of perlite & pumice with the bark and Turface because I need the added moisture. I live on the coast in S. California and the wind blows up the hill everyday drying the container plants out, and when the hot Santa Ana winds blow, well that's a whole nother story.

    I have enough perlite to get me by, so I'm repoting something today!


  • jojosplants

    Hi Jerry,
    1/8" is too big for screening turface. You can use insect screen. I also use it to screen the dust and fines out of the perlite.

    I'm using perlite for my gritty mix at the moment too. I can't find the grit here.

    The amounts do change a little if using perlite. Here's what Al suggests.

    It is suggested~
    4 screened perlite
    3 screened bark
    2 screened Turface

    will be about the same water retention as the original

    1 screened bark
    1 screened Turface
    1 crushed granite (grower size) or #2 cherrystone

    Adjust as required from there.

    I'm trying to sift today, anxious to get some tree's done, but wind is making it not fun. lol!

    Good luck with your re potting today.


  • PRO

    What JJ said.


  • JerryVentura Jordan

    Thank you so much JoJo, I knew I was missing something, I knew I was seeing smaller particles in some of the pictures. I was wondering though, if the granite only holds the water on it's surface, then why would you need to change the ratio and have more perlite to hold more moisture when by it's nature it is porous? Is it because it's in smaller particles? I'm going to mix it in the quantity you suggest, I'm just an eager apprentice.

    Thank you to all of you, I've learned so much in the past couple weeks, everyone around me is sick of hearing me talk about soil.


  • PRO

    Lolol - everyone around HERE is sick of me talking about soil too, but the questions and people with difficulties related to their soils just keep coming.

    Got the question covered JJ?


  • JerryVentura Jordan

    Ok, so I tried the insect screen, that left a lot more in the pan, but they're smaller than a bb. From what I read above, wouldn't that be like the bb's in the pudding? I thought I was supposed to get everything to be between 1/8-1/4? If there are to many particles of the Turface and perlite that are smaller than the bark, and there percentage is greater than the sum of the bark, doesn't that clog things up?

    I keep reading the first part above, sorry for all the questions. I would just do what you say, and I am, but I just like to understand why something is, or done a certain way. I don't want to make to many mistakes.


  • PRO

    Screening the Turface through insect screen leaves you with the Turface being a little smaller than Ideal, but it's something I'm willing to live with because the other properties are so great. If I could find a calcined clay in a size just a smidgen larger, I'd be all over it. However, since the granite and bark I use are slightly larger than the Turface and still small enough that the mix remains homogeneous, water won't perch. IF the granite is too small & the bark too large, as in what happened to Julie, you WILL get perched water and more water retention than what you want. Still, it will be less water retention and a lower PWT than in peaty soils, but too much to be considered ideal. The ideal soil holds lots of water but no perched water.

    In a perfect world, the Turface and granite would be just under 1/8" to just over 1/8", and the bark 1/8-1/4" to allow for some breakdown over time.

    I use Turface screened through insect screen and #2 cherrystone, which is prescreened 1/8-3/16", and 1/8-1/4" prescreened fir bark and I get no perched water at all.

    A little perched water to me is a big deal because I grow a LOT of material in shallow containers, but it won't be as significant to those growing in deeper containers like nursery cans. If you're concerned, you can always add a wick and make it a nonissue.


  • ligreenthumb

    Good morning to all.

    I'd like some more info about the soil longevity for the various mixes as suggested at the start of the post so I can plan how much material I need for pilot experiments. ["I have seen advice that some highly organic (practically speaking - almost all container soils are highly organic) container soils are productive for up to 5 years or more. I disagree and will explain why if there is interest."] If there is already a thread/link, please let me know where to find. Can some/any of the components be re-used? What can be done with the spent mixture(s)?

    Would someone please provide a quick recap of the "right" type of bark vs the "wrong" type. (I understand the size range I am after.) I like the idea of the pre-screened ReptiBark, but wonder if there are more cost effective strategies if I know the right information. Also, what screening methods do people use that are easy to get/make and widely available?

    Thanks again.

  • jodik_gw

    General gardening knowledge and common sense tell me that any highly organic soil cannot possibly remain viable for a span of 5 years as container medium, due to basic decomposition of the organic matter it's comprised of. In fact, compaction of fine particles happens swiftly, and I wouldn't use a bagged organic soil for more than one growing season... if I used it, at all. Knowing, as I do, that there is a great difference between growing in the ground, and growing within the confines of containers, I avoid organic in pots and save it for the beds outside.

    In the gritty mix, the one ingredient that will eventually break down is the fir bark, and that can take quite a long time. Al can explain how long it will take, and why... that bit of information escapes me at the moment. I'm looking at using a batch of gritty mix for at least 3 years before re-potting.

    I would screen the spent mixture, removing the finer particulate, and re-use what portion still looked viable. The spent part will be spread over my outdoor raised beds. Or, I could simply dump all of it on my raised beds and work it in, which will help aeration, and begin anew for my containers. It will depend largely upon my gardening budget at the time.

    ReptiBark is not cost effective if large amounts are required. It would be more prudent to locate a bulk fir bark item in a "fine" size.

    If you're handy, nice screens can be made using insect screening, or the screen size of choice, and a wooden frame. You can make it to fit whatever receptacle you'll be screening over and storing the material in. Or, you can purchase ready made bonsai screens, though they would impede quick screening of bulk items due to their smaller size.

    I'm sure someone will be along shortly to give information on where to get screening, and to answer other questions that I can't, or that I've forgotten. The above is how I'd do it, though.

  • AprilAugust

    Hi All,

    What awesome info to have stumbled upon! Thanks Al and everyone!

    I'm hoping someone can answer a question for me.
    So this is my first season gardening and I'm planning on using containers. I plan to start seeds this week, and a few days ago (before reading this thread!) I bought a bag of some organic seed starting mix (that I now plan to return, I think...?) My question is this: Is the 5-1-1 mix suitable for starting seeds for veggies? And for growing strawberries too? (Or do I hold onto the seed starting mix I bought?)
    I'm thinkin' the answer is to use the 5-1-1 mix from the get-go, but I don't really know, ya know?!

    Thanks much and be well,

  • greenman28 NorCal 7b/8a

    Hello, April!

    We're glad to have you. Welcome aboard!

    First, strawberries will do wonderfully in the 5-1-1. I just saw a good buddy's strawberries
    in 5-1-1 under grow-lights last night. He has them in 4-inch containers and he already has berries.

    Secondly, I use the Gritty Mix to start my seeds: peppers, squash, melon, maple, osage, castor bean.
    As the seedlings grow larger, I transfer them into 5-1-1 to take advantage of the slightly increased
    moisture retention.


  • edweather USDA 9a, HZ 9, Sunset 28

    Hi, There is a product on Fafard's website called Organic Soil Conditioner, made of processed pine bark, limestone, and gypsum. Is this ok for the 511 mix? If it is, do I still need to add the lime? My brain is spinning right now and I think I saw in a thread that this is good for the 511. There are several Fafard retailers in my area. I'm having no luck "yet" with finding the pine bark fines, but I still have a lot of searching left to do. If this Fafard product isn't usable, does anyone know of a source in the Syracuse NY area for the pine bark fines? Thanks.

  • PRO

    I've never seen it or used it. Fafard's soil blends #51L or #3 are both pine bark-based soils and pretty good right out of the bale, though. I have used Fafard's aged pine bark in soils, and for me it's borderline too fine. It's so fine you would probably want to forgo the peat and even add a little extra perlite to it.


  • edweather USDA 9a, HZ 9, Sunset 28

    OK, I really appreciate the advice. Well.....back to the drawing board. It's still very early in the season up here and most garden centers, big boxes, and Walmarts aren't even set up for spring. Who know's what they'll eventually get in. I don't need the 511 'til May 1st at the earliest. I'm sure something will turn up. There is a big mulch place a short drive from here that has hemlock bark mulch. I noticed that you said hemlock is ok to use. Thanks.

  • PRO

    Lol - you've been doing your homework (hemlock). I like the positive attitude, too!


  • edweather USDA 9a, HZ 9, Sunset 28

    FWI, I just ordered a 2 cu. ft. bag of perlite online from Home Depot for $17 + tax, w/free shipping. I thought that was a pretty good price.

  • PRO

    Not sure I should say anything, but I buy 4 cu ft bags for $10.50 (at least that's what they were last year). If I had room & thought I could ever use it, it's also available in a 60 cu ft bag @ $105.


  • edweather USDA 9a, HZ 9, Sunset 28

    No problem, I knew I was leading with my chin in some respects with that one, but for around here that was the best I found after quite a lot of looking. Hopefully it will help someone else. I hope I don't see it too much cheaper in the near future. No buyers remorse "yet." So is your source online? I'm DEFINITELY still in the market for some inexpensive pine bark fines:) That's the last piece of the puzzle. I'll buy a bunch of pine bark mulch and run over it with my truck a bunch of times if I have to. Lol. I must know someone with a chipper, I just haven't figured out who yet. I think using my wife's food processor to chip the bark is out of the question:)

  • PRO

    I have a wholesaler that supplies nurseries with all sorts of products about a half hour away. With a business license, I buy wholesale.

    'Al-Par Peat' in Elsie, MI is the company I get it from. I buy some CRF fertilizers & peat bales from them, too. For years, I used to buy pine bark from them too (cheap), but lately they've been carrying this stuff with ground peanut shells and rice hulls in it & I don't care for it.

    Good luck! ;-)


  • jojosplants

    I paid $13 for my 2 cu. ft. bag at Home Depot, commercial grade.

  • GrnThum


    Just curious, I have a question about sphagnum peat vs sphagnum moss. By mistake, I purchased sphagnum moss at the onset of making the 511 mix. I mixed one batch and used it for one of my 3 plants.

    When I realized that I was using the moss instead of the sphagnum peat, I threw it out and purchased the correct one and used it to make the mix for the other 2 plants I have.

    My question is this, is it possible that the presence of the sphagnum moss in this one container could somehow attract any pests?

    The reason I ask is that I saw about a couple of black, winged, fast-moving pests (maybe thrips or gnats?) around this plant today.

    Upon further inspection, I shuffled some of the top mix and saw a single, tiny larva(e) crawling in the medium and suspected that I have pests breeding in my container.

    And afterwards, as I shook the container, a fast crawling, winged pest climbed out of the mix, and up the side of the container. I sprayed this plant with some insecticdal soap and plan on repotting it using the sphagnum peat moss instead.

    So could this (sphagnum moss) be the reason for pest-sightings? I want to solve a potential big problem now, before the real bug season begins.

    By the way, I haven't watered this plant for like a week and it still seems to be moist inside. I had watered every 3 days prior to the last time.

  • meyermike_1micha

    What kine of bark did you start with Sam?

    Did it already have some fines in it? If so, that along with the peat fraction will hold way to much moisture and will certainly be a breeding ground for fungus gnats. Good catch:-)


  • edweather USDA 9a, HZ 9, Sunset 28

    Al, Which bark would be better to use for the 5:1:1 mixture? I might have 2 choices. Pure Hemlock bark, and the second is a mixture of White Pine bark, Red pine bark, and Spruce bark. Thanks, Ed

  • PRO

    I used chipped hemlock bark I got from a local mill a long time ago, and it worked ok. I've never used spruce though, so I can't really say which would be better. Sorry. I wouldn't think there would be a significant difference in the chemical composition, though. I would probably let the texture be my guide & take whichever one fits the most favorable size profile.


  • edweather USDA 9a, HZ 9, Sunset 28

    OK, thanks. I'll be giving the stuff a looksee next week. To be continued....

  • GrnThum

    I used repti- bark in the mix. Is the sphagnum moss bad for the mix though? I wanted to know if I should repot with the sphagnum peat instead?

  • meyermike_1micha

    Honestly. Sam, I never use peat with repti-bark.

    I only use ingredients roughly about the same size such as turface and or granite. I am not sure if using such fine particles as moss, I think is almost dust, can settle into an area that collects to much moisture that is much finer and more dense than the repti-bark.

    Maybe someone her can answer this.

    I tend to use decomposted bark with peat for my 5.1.1 so it mixes well and dries out evenly, although this too retains more moisture by nature.

    I can tell you that fungus gnats do not breed well in uncomposted bark such as repti-bark, but they may love the fine moss where that has settled between the bigger bark spaces.

  • Kinder Devonshire

    Hello Al.

    I am getting ready to start making my mixes, I am going to be using the gritty and the 511 mixes for my indoor and outdoor plants. I do have a few questions.

    On an earlier post that I can't find again (probably because I have read so many posts here in the last couple of weeks I lost track of it) someone asked you questions about a bark mulch called 'Greensmix Bark Mulch' carried at Lows. My Lows carries it as well. Will it be suitable for both the gritty mix and the 511? The bark size is up to 3/8".

    Turface is not available in my area, I shall be using the NAPA oil dry. Can I use it instead of the perlite in the 511 mix? I believe it will retain more moisture, but as I live in a dry area this would be a good thing.

    I believe I read in a post that if I am using a complete fertilizer like Foliage Pro that I would not have to use the lime in the 511 or the gypsum in the gritty. Is this true?


  • PRO

    If the Greensmix is pine bark and dust to 3/8, it should be perfect for the 5:1:1 mix. You should be able to screen it and use it for the gritty mix too, if you like, and use the leftover fines in the 5:1:1 mix - no waste. ;-)

    If you use the floor dry in lieu of perlite, you might want to go a little easier on the peat fraction, but you'll ultimately have to be the judge of that.

    DO use lime in the 5:1:1 with FP 9-3-6, but don't use gypsum in the gritty mix, or add Epsom salts to the fertilizer solution.

    Would you hold any replies until I get set up with the next thread? This thread is about to top out at 150 posts, and I'd like to link the last post here to the new thread, and that might take me a half hr or so to get it set up. Thanks!


  • PRO

    Please follow the link to the continuation of this thread. It will take you to Part XIII

    Thanks to everyone for being a part of making this thread so much fun for all of us!


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