Your shopping cart is empty.

Tapla's 5-1-1 Container Mix in More Detail

February 26, 2009

I recently joined the forum and discovered Al's 5-1-1 Mix, but I had several questions that Al was kind enough to answer by email. I also found the answers to other questions in several different threads. I thought it would be useful to organize all of the info in one place so that we could have easy access to it. 98% of the following has been cut/pasted from Al's postings, and I apologize in advance if I have somehow misquoted him or taken his ideas out of proper context. The only significant addition from another source is the Cornell method of determining porosity, which I thought would be germane. I have used a question and answer format, using many questions from other members, and I apologize for not giving them proper credit. Thanks to all who contributed to this information. Now, here's Al:

Tapla's 5-1-1 Mix

5 parts pine bark fines

1 part sphagnum peat

1-2 parts perlite

garden lime

controlled release fertilizer (not really necessary)

a micro-nutrient source (seaweed emulsion, Earthjuice, Micro-max, STEM, etc,)

Many friends & forum folk grow in this 5-1-1 mix with very good results. I use it for all my garden display containers. It is intended for annual and vegetable crops in containers. This soil is formulated with a focus on plentiful aeration, which we know has an inverse relationship w/water retention. It takes advantage of particles, the size of which are at or just under the size that would guarantee the soil retains no perched water. (If you have not already read Al's treatise on Water in Container Soils, this would be a good time to do so.) 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 ensure normal water/nutrient uptake and root function.

I grow in highly-aerated soils with the bulk of the particles in the 1/16"-1/8" size, heavily favoring the larger particles, because we know that perched water levels decrease as particle size increases, until finally, as particle size reaches just under 1/8" the perched water table disappears entirely.

Ideal container soils will have a minimum of 60-75% total porosity. This means that when dry, in round numbers, nearly 70% of the total volume of soil is air. The term 'container capacity' is a hort term that describes the saturation level of soils after the soil is saturated and at the point where it has just stopped draining - a fully wetted soil. When soils are at container capacity, they should still have in excess of 30% air porosity. Roughly, a great soil will have about equal parts of solid particles, water, and air when the soil is fully saturated.

This is Cornell's method of determining the various types of porosity:

To ensure sufficient media porosity, it is essential to determine total porosity, aeration porosity, and water-holding porosity. Porosity can be determined through the following procedure:

* With drainage holes sealed in an empty container, fill the container and record the volume of water required to reach the top of the container. This is the container volume.

* Empty and dry the plugged container and fill it with the growing media to the top of the container.

* Irrigate the container medium slowly until it is saturated with water. Several hours may be required to reach the saturation point, which can be recognized by glistening of the medium's surface.

* Record the total volume of water necessary to reach the saturation point as the total pore volume.

* Unplug the drainage holes and allow the water to freely drain from the container media into a pan for several hours.

* Measure the volume of water in the pan after all free water has completed draining. Record this as the aeration pore volume.

* Calculate total porosity, aeration porosity, and water-holding porosity using the following equations (Landis, 1990):

* Total porosity = total pore volume / container volume

* Aeration porosity = aeration pore volume / container volume

* Water-holding porosity = total porosity - aeration porosity

The keys to why I like my 3-1-1 mix:

It's adjustable for water retention.

The ingredients are readily available to me.

It's simple - 3 basic ingredients - equal portions.

It allows nearly 100% control over the nutritional regimen.

It will not collapse - lasts longer than what is prudent between repots.

It is almost totally forgiving of over-watering while retaining good amounts of water between drinks.

It is relatively inexpensive.

Q. Why do you use pine bark fines? 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 natures 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.

Q. What is the correct size of the fines? 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.Pine bark fines are partially composted pine bark. Fines are what are used in mixes because of the small particle size. There will be a naturally occurring "perched water table" (PWT) in containers when soil particulate size is under about .125 (1/8) inch, so best would be particulates in the 1/16 - 3/16 size range with the 1/16-1/8 size range favored.

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 ½ BB size I leave it out of soils. Compost is too 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.

Q. Do you use partially composted pine bark fines? Yes - preferred over fresh fines, which are lighter in color.

Q. I found some Scotchman's Choice Organic Compost, which is made of pine bark fines averaging about 1/8" in size, and, after adding all ingredients, the 5-1-1 Mix had a total porosity of 67% and an aeration porosity of 37%. Is that all right? Yes, that is fine.

Q. What kind of lime do you use? Dolomitic.

Q. What amount of lime should I add if I used 10 gal of pine bark fines and the corresponding amount of the other ingredients? @ 5:1:1, you'll end up with about 12 gallons of soil (the whole is not equal to the sum of the parts when you're talking about soils), so I would use about 10-12 Tbsp or 2/3-3/4 cup of lime.

Q. What grade of coarseness for the lime? Most is sold as garden lime, which is usually prilled powder. Prilling makes it easier to use in drop & broadcast spreaders. The prills dissolve quickly. The finer the powder the quicker the reactive phase is finished. Much of the Ca and Mg will be unavailable until the media pH equalizes so the plant can assimilate the residual elements. Large pieces of lime really extend the duration of the reactive phase.

Q. Does this mean that I need to make up the soil in advance? Yes. 2 weeks or so should be enough time to allow for the reaction phase to be complete & residual Ca/Mg to become more readily available from the outset .

Q. During those 2 weeks, do I need to keep turning it and moistening it? No

Q. Can I go ahead and fill my 3-gal. containers, stack them 3-high, and cover the top one to prevent moisture loss during the waiting period? Something like that would be preferred.

Q. The perlite I use has a large amount of powder even though it is called coarse. Do I need to sift it to get rid of the powder? Not unless it REALLY has a lot - then, the reason wouldn't be because of issues with particle size - it would be because you had to use larger volumes to achieve adequate drainage & larger volumes bring with it the possibility of Fl toxicity for some plants that are fluoride intolerant.

Q. What about earthworm castings (EWC)? I think 10% is a good rule of thumb for the total volume of fine particles. I try to limit peat use to about 10-15% of soil volume & just stay away from those things that rob aeration & promote water retention beyond a minimal perched water table. If you start adding 10% play sand, 10% worm castings, 10% compost, 10% peat, 10% topsoil, 10% vermiculite to a soil, before long you'll be growing in something close to a pudding-like consistency.

Q. Do you drench the mix with fertilized water before putting in containers? No - especially if you incorporate a CRF. It will have lots of fertilizer on it's surface & the soil could already be high in solubles. If you added CRF, wait until you've watered and flushed the soil a couple of times. If you didn't use CRF, you can fertilize with a weak solution the first time you water after the initial planting irrigation.

Q. How much of the micronutrients should I add if I am going to be fertilizing with Foliage Pro 9-3-6, which has all the micronutrients in it? You won't need any additional supplementation as long as you lime.

Q. Just to make sure I understand, are you saying I don't need to use Foliage Pro 9-3-6 until after the initial watering right after planting even if I don't use a CRF? And no additional micronutrients? That's right - on both counts.

Q. Do I need to moisten the peat moss before mixing with the pine bark fines? It helps, yes.

Selections from Notes on Choosing a Fertilizer

A) Plant nutrients are dissolved in water

B) The lower the nutrient concentration, the easier it is for the plant to absorb water and the nutrients dissolved in the water - distilled water is easier for plants to absorb than tap water because there is nothing dissolved in distilled water

C) The higher the nutrient content, the more difficult it is for plants to absorb water and the nutrients dissolved in water

D) To maximize plant vitality, we should supply adequate amounts of all the essential nutrients w/o using concentrations so high that they impede water and nutrient uptake.

All that is in the "Fertilizer Thread" I posted a while back.

Q. Do you use the Dyna-Gro Foliage Pro 9-3-6 exclusively throughout the life of the plant, or change to something else for the flowering/fruiting stage? I use lots of different fertilizers, but if I had to choose only one, it would likely be the FP 9-3-6. It really simplifies things. There are very few plants that won't respond very favorably to this fertilizer. I use fast soils that drain freely & I fertilize at EVERY watering, and it works extremely well.

If you are using a soil that allows you to water freely at every watering, you cannot go wrong by watering weakly weekly, and you can water at 1/8 the recommended dose at every watering if you wish with chemical fertilizers.

Q. What about the "Bloom Booster" fertilizers? To induce more prolific flowering, a reduced N supply will have more and better effect than the high P bloom formulas. When N is reduced, it slows vegetative growth without reducing photosynthesis. Since vegetative growth is limited by a lack of N, and the photosynthetic machinery continues to turn out food, it leaves an expendable surplus for the plant to spend on flowers and fruit. There are no plants I know of that use anywhere near the amount of P as they do N (1/6 is the norm). It makes no sense to me to have more P available than N unless you are targeting a VERY specific growth pattern; and then the P would still be applied in a reasonable ratio to K.

Somewhere along the way, we curiously began to look at fertilizers as miraculous assemblages of growth drugs, and started interpreting the restorative effect (to normal growth) fertilizers have as stimulation beyond what a normal growth rate would be if all nutrients were adequately present in soils. ItÂs no small wonder that we come away with the idea that there are Âmiracle concoctions out there and often end up placing more hope than is reasonable in them.

What I'm pointing out is that fertilizers really should not be looked at as something that will make your plant grow abnormally well - beyond its genetic potential . . . Fertilizers do not/can not stimulate super growth, nor are they designed to. All they can do is correct nutritional deficiencies so plants can grow normally.

Q. Should I use organic ferts or chemical ferts in containers? Organic fertilizers do work to varying degrees in containers, but I would have to say that delivery of the nutrients can be very erratic and unreliable. The reason is that nutrient delivery depends on the organic molecules being broken down in the gut of micro-organisms, and micro-organism populations are boom/bust, varying widely in container culture.

Some of the things affecting the populations are container soil pH, moisture levels, nutrient levels, soil composition, compaction/aeration levels ..... Of particular importance is soil temperatures. When container temperatures rise too high, microbial populations diminish. Temps much under 55* will slow soil biotic activity substantially, reducing or halting delivery of nutrients.

I do include various formulations of fish emulsion in my nutrient program at certain times of the year, but I never rely on them, choosing chemical fertilizers instead. Chemical fertilizers are always immediately available for plant uptake & the results of your applications are much easier to quantify.

Q. Should I feed the plants every time I water? In a word, yes. I want to keep this simple, so IÂll just say that the best water absorption occurs when the level of solutes in soil water is lowest, and in the presence of good amounts of oxygen. Our job, because you will not find a sufficient supply of nutrients in a container soil, is to provide a solution of dissolved nutrients that affords the plant a supply in the adequate to luxury range, yet still makes it easy for the plant to take up enough water to be well-hydrated and free of drought stress. All we need to do is supply nutrients in approximately the same ratio as plants use them, and in adequate amounts to keep them in the adequate to luxury range at all times. Remember that we can maximize water uptake by keeping the concentrations of solutes low, so a continual supply of a weak solution is best. Nutrients donÂt just suddenly appear in large quantities in nature, so the low and continual dose method most closely mimics the nutritional supply Mother Nature offers. If you decide to adopt a "fertilize every time you water" approach, most liquid fertilizers can be applied at ¾ to 1 tsp per gallon for best results.

The system is rather self regulating if fertilizer is applied in low concentrations each time you water, even with houseplants in winter. As the plantÂs growth slows, so does its need for both water and nutrients. Larger plants and plants that are growing robustly will need more water and nutrients, so linking nutrient supply to the water supply is a win/win situation all around.

You can tell you've watered too much (or too little - the response is the same - a drought response) when leaves start to turn yellow or you begin to see nutritional deficiencies created by poor root metabolism (usually N and Ca are first evident). You can prevent overwatering by A) testing the soil deep in the container with a wood dowel ... wet & cool - do not water, dry - water. B) feeling the wick & only watering when it's dry C) feel the soil at the drain hole & only water when it feels dry there.

Soils feel dry to our touch when they still have 40-45% moisture content. Plants, however, can still extract water from soils until they dry down to about 25-30%, so there is still around a 15% cush in that plants can still absorb considerable moisture after soils first feel dry to us.

Q. When you water/fertilize, do you give it enough that 10% leaches out the bottom each time? Yes, I try to do that at every watering. Remember that as salts accumulate, both water and nutrient uptake is made more difficult and finally impaired or made impossible in severe cases. Your soils should always allow you to water so that at least 10-15% of the total volume of water applied passes through the soil and out the drain hole to be discarded. This flushes the soil and carries accumulating solutes out the drain hole. In addition, each thorough watering forces stale gases from the soil. CO2 accumulation in heavy soils is very detrimental to root health, but you usually can't apply water in volume enough to force these gases from the soil. Open soils allow free gas exchange at all times.

Q. Should I elevate my pots? The container will not drain the same % of water if it's sitting in a puddle, but the % won't be particularly significant. What will be significant is: if water (in a puddle) is able to make contact with the soil in the container through surface tension and/or capillarity, it will "feed" and prolong the saturated conditions of any PWT that might be in the container. However, if water can soak in or if it will flow away from the containers, there's no advantage to elevating when you're not using a wick.

Q. I like a pH of about 5.7. Is that about right? That's a good number, but you won't have any way of maintaining it in your soil w/o some sophisticated equipment. I never concern myself with media pH. That doesn't mean you should ignore water pH, though. It (water pH) affects the solubility of fertilizers; and generally speaking, the higher the water pH, the lower the degree of nutrient solubility.

Q. How do you repot? Some plants do not take to root-pruning well (palms, eg), but the vast majority of them REALLY appreciate the rejuvenational properties of major root work. I'm not at all delicate in my treatment of rootage when it comes time to repot (completely different from potting-up). Usually I chop or saw the bottom 1/2-2/3 of the root mass off, bare-root the plant, stick it back in the same pot with ALL fresh soil, use a chopstick to move soil into all the spaces/pockets between roots, water/fertilize well & put in the shade for a week to recover. I should mention that this procedure is most effective on plants with woody roots, which most quickly grow to be inefficient as they lignify, thicken, and fill the pot. Those plants with extremely fibrous root systems are easier to care for. For those, I usually saw off the bottom 1/2 - 2/3 of the roots, work a chopstick through the remaining mat of roots, removing a fair amount of soil, prune around the perimeter & repot in fresh, well-aerated soil.

I find that time after time, plants treated in this fashion sulk for a week or two and then put on a huge growth spurt (when repotted in spring or summer). Growth INVARIABLY surpasses what it would have been if the plant was allowed to languish in it's old, root-bound haunts. Potting up is a temporary way to rejuvenate a plant, but if you look ate a long-term graph of plants continually potted-up, you will see continual decline with little spurts of improved vitality at potting-up time. This stress/strain on plants that are potted-up only, eventually takes its toll & plants succumb. There is no reason most houseplants shouldn't live for years and years, yet we often content ourselves with the 'revolving door replacement' of our plants when just a little attention to detail would allow us to call the same plant our friend - often for the rest of our lives if we prefer.

Q. Is there any rule of thumb as to how often to root prune? I'm going to answer as if you included 'repotting' in your question. There is no hard, fast rule here. Some of you grow plants strictly for the blooms, and some plants produce more abundant blooms in containers when they are stressed in some manner. Often, that stress is in the form of keeping them root-bound. I'll talk about maintaining a plant's vitality & let you work out how you want to handle the degree of stress you wish to subject them to, in order to achieve your goals. Before I go on, I'd like to say that I use stress techniques too, to achieve a compact, full plant, and to slow growth of a particularly attractive plant - to KEEP it attractive. ;o) The stress of growing a plant tight can be useful to a degree, but at some point, there will be diminishing returns.

When you need to repot to correct declining vitality:

1) When the soil has collapsed/compacted, or was too water-retentive from the time you last potted-up or repotted. You can identify this condition by soil that remains wet for more than a few days, or by soil that won't take water well. If you water a plant and the soil just sits on top of the soil w/o soaking in, the soil has collapsed/compacted. There is one proviso though: you must be sure that the soil is wet before you assess this condition. Soils often become hydrophobic (water repellent) and difficult to rewet, especially when using liquid organic fertilizers like fish/seaweed emulsions. Make sure this effect is not what you're witnessing by saturating the soil thoroughly & then assessing how fast the water moves downward through the soil. The soils I grow in are extremely fast and water disappears into the mix as soon as it's applied. If it takes more than 30 seconds for a large volume of water to disappear from the surface of the soil, you are almost certainly compromising potential vitality.

I'll talk about the potential vitality for just a sec. Plants will grow best in a damp soil with NO perched water. That is NO saturated layer of water at the bottom of the pot. Roots begin to die a very short time after being subjected to anaerobic conditions. They regenerate again as soon as air returns to the soil. This cyclic death/regeneration of roots steals valuable energy from the plant that might well have been employed to increase o/a biomass, and/or produce flowers and fruit. This is the loss of potential vitality I refer to.

2) When the plant is growing under tight conditions and has stopped extending, it is under strain, which will eventually lead to its death. "Plants must grow to live. Any plant that is not growing is dying." Dr. Alex Shigo Unless there are nutritional issues, plants that have stopped extending and show no growth when they should be coming into a period of robust growth usually need repotting. You can usually confirm your suspicions/diagnosis by looking for rootage "crawling" over the soil surface and/or growing out of the drain hole, or by lifting the plant from its pot & examining the root mass for encircling roots - especially fat roots at the container's edge. You'll be much less apt to find these types of roots encircling inner container perimeter in well-aerated soils because the roots find the entire soil mass hospitable. Roots are opportunistic and will be found in great abundance at the outside edge of the soil mass in plantings with poor drainage & soggy soil conditions - they're there looking for air.

3) When the soil is so compacted & water retentive that you must water in sips and cannot fully flush the soil at each watering for fear of creating conditions that will cause root rot. This isn't to say you MUST flush the soil at every watering, but the soil should drain well enough to ALLOW you to water this way whenever you prefer. This type of soil offers you the most protection against over-watering and you would really have to work hard at over-fertilizing in this type of soil. It will allow you to fertilize with a weak solution at every watering - even in winter if you prefer.

Incidentally, I reject the frequent anecdotal evidence that keeping N in soils at adequacy levels throughout the winter "forces" growth or "forces weak growth". Plants take what they need and leave the rest. While there could easily be the toxicity issues associated with too much fertilizer in soils due to a combination of inappropriate watering practices, inappropriate fertilizing practices, and an inappropriate soil, it's neither N toxicity NOR the presence of adequate N in soils that causes weak growth, it's low light levels.

Q. Is there any rule of thumb as to how often to remove and replace the old soil? Yes - every time you repot.

As always, I hope that those who read what I say about soils will ultimately take with them the idea that the soil is the foundation of every container planting & has effects that reach far beyond the obvious, but there is a snatch of lyrics from an old 70's song that might be appropriate: "... just take what you need and leave the rest ..." ;o)

Comments (253)

  • Andi C

    i think there are people who have grown japanese maple in these container mixes before.

    i don’t know enough about japanese maple specifically, but when you pick a mix you need to consider multiple factors (assuming you can get ingredients for both mixes).

    gritty mix will provide better drainage/aeration, mix lasts longer. downsides include you need to water more frequently, it is heavier, more expensive ingredients. how large is the tree and container btw?

    5-1-1 is usually easier to make - less expensive and often the ingredients are easier to find. it is lighter than gritty, has more water retention (but less aeration). 511 will last 1-2 seasons before needing to be repot and root pruned

    if your japanese maple is in big box potting soil, both gritty and 511 will increase the max potential of your plant. you also should monitor the new mix to see how often it will need watering

  • huanle0
    Here is the pictute of my JM Crimson Queen species which is still in the original nursery pot for the last 3 years. It is doing fine but not thriving as much. Infact this year it is suffering from some die back on a few branches which I already pruned it down. (This picture was taken in early spring).

    I have a few more questions for you experts out there:

    1/ Let just say if I decided to go with either 511 or gritty mix, how often the watering goes during the dormant season (winter) ?

    2/ Does JM needs alot of fertilizer and what type?

    3/ Can I use the fir barks (Repti barks) to substitute for Pine barks? The reason is all I could find Pine mini nuggets not Pine fine barks. Mini nuggets are still a bit big for these type of mix.

    Last but not least, thanks to Gardengal48 and Andi C for a quick response. Very much appreciates. I am sure I will have a lot more questions and need help from you guys as I am starting to experiment with these type of soil mix and so keen to make it work for my JM. I am a JM lover...LOL

    Huan. L

  • gardengal48 (PNW Z8/9)

    Because of my climate, my JM's stay outside all winter so I pay no attention to watering during this period....plenty of rainfall :-) But they don't need a lot if storing inside - just enough to keep the soil barely moist to the touch. And they do not have high nutrient demands. I dose mine wiith Osmocote Plus each spring right as they start to leaf out and that lasts the whole season. If you choose not to use a CRF like Osmocote, a half strength liquid fertilizer like Foliage Pro applied every couple of weeks during the growing season is more than adequate. And I use fir bark as well, as it tends to be much more plentiful and easy to find in my area than is pine bark

    btw, the 5-1-1 mix holds up much longer for me than 1-2 seasons before needing to be replaced. I usually repot and root prune every 3-5 years, depending on tree growth and container size and the 5-1-1 is still in very good condition at that time.

  • Andi C

    1. watering requirements: poke the soil with your index finger and see if it is dry a couple cm down. if it’s dry then time to water. during dormancy, most of my plants get watered 1/week but you need to monitor.

    2. not sure. osmocote plus is great for almost all plants.

    3. i think people have tried reptibark. the particle size is similar to pbf but some other characteristics are different (maybe acidity, ion transfer, etc). iirc it’s also very expensive.

    yoh could grind down pine bark nuggets/mulch and make your own pbf. also can go to a local specialty nursery and see what brand/mix they use

  • stuartlawrence (7b L.I. NY)

    For Japanese Maples I would recommend applying a quarter or half the dosage of Osmocote plus. That's what I've been using and I get a lot of new growth on my Japanese Maples in pots.

  • PRO

    Generally growers that are at least skilled enough to keep their trees alive (in pots) don't have a problem getting maples to grow, the problem arises from not knowing how to control or manage growth properly by pinching appropriately. I only occasionally make use of CRFs (like Osmocote, Dynamite, et al) because I like the control afforded by soluble synthetic fertilizers. Since the delivery rate of CRFs is primarily controlled by temperatures, when we should be pulling back on the fertilizer reins during the heat of summer, CRFs are pouring it on, which can cause a lot of spoiled foliage and root injury that I for one can do without.


  • mblan13

    Huanle0, I have several JM's in gritty mix, and they are doing very well. It holds more water than most would think, I only water mine if we don't get a good soaking rain for 7 days, or 4-5 in 90+ temps. If you only have one potted JM, the extra watering over the 5-1-1 is no big deal... If you have a bunch, the 5-1-1 might be a better chioce (?). Here is a must read for trees in pots, if you have not already found it.

    1) I generally put mine in the garage when temps fall regularly to 32F/0C. Basically Jan and Feb. I water once a month these months.

    2) No, they don't need a lot of fretilizer. I use DynaGro Foliage Pro and Pro TeKt in spring and early summer and none in the fall or winter. You don't want to promote a flush of growth in the fall that will not have the time to harden off before winter.

    3) If memory serves, fir bark is actually preferred, as it breaks down a bit slower than pine bark... if I'm wrong on that it is at least as good as pine bark.

  • gardengal48 (PNW Z8/9)

    Al, I have only ever used Osmocote on my JM's (actually on all my containered trees) just for ease of management and I have never experienced any root issues or excessive foliar growth as a result. But maybe that's because summers here are just not that hot (compared to most of the rest of the US) so the disbursement of nutes from the CRF is more evenly distributed during the growing season. And I tend not to be very heavy handed with it anyway :)

    But I will keep that caution in mind going forward!

  • huanle0

    Thank you to all of you for quick responses on my question about growing JM in container.

    I think I will try to attemp to use both the 511 and gritty mix and see how the JMs will thrive in it.

    BTW I have a few JMs both the Red species as Red Dragon and Crimson Queen , Orangeola and the green leaf Viridis waterfall.

    The only problem that worrying me is how would the JMs will response to these kind of mix in the Winter time when I move them inside the unheated garage. Do I have to mulch and wrap the pots to keep them warm a bit because the last 2017 winter it was so cold that the soil was actually freezed up and I think this was the reason why my Crimson Queen suffered a die back on a few branches in early spring.

    Also I would like to know when is the good time to transplanting the JMs to the new pot with the new mix. It is kind of very hot and humid this summer in Toronto at the moment. Should I wait till September or when the weather cooling down a bit?

    Any advices would help. Thanks again guys.

    Here are the 3 JMs that I want to keep in the container. The Red Crimson Queen, green Viridis waterfall and The Orangeola.

  • PRO

    If you're going to repot in the fall, you need to try to keep roots from freezing over the winter, as new roots are very tender. If you wait until spring, you'll want to repot just as buds well as they're getting ready for the spring push.

    I'm z5a/6b here and I over-winter all my maples in an attached/unheated garage. There are 3 types of frozen roots. The first occurs when the water in the soil freezes, and that's no problem for temperate maples. Next, is inter-cellular water that occurs in tissues between plant cells - still no problem. There IS a problem, however, when intra-cellular water freezes. When water inside of cells freezes the ice crystal formation does irreparable damage. Acer palmatum is generally listed as safe to about 14 or 15*F, but to be on the safe side, try to keep root temp no colder than 20-25*, as all roots do not have the same level of resistance to cold. Young, fine roots are the first to succumb, while older, more lignified roots don't seem to mind the low temps.

    I grow all maples in the gritty mix and have no problems with root injury due to cold, nor would I expect injury if growing in the 5:1:1 mix.


  • huanle0

    Hello Al,

    Thanks for the previous posts Al.

    Got another question for you :)

    Can I use Worm Casting to fertilize container JM that is growing in 511/gritty mix soil?

    Thanks Al

  • greenman28 NorCal 7b/8a

    Huanle, while you *can* technically fertilize the 511 with organics, there are some good reasons not to. Primarily, with worm castings or other fine particulate, the particulate will eventually compromise drainage and increase moisture retention/decrease aeration, which is one of the greatest benefits of this mix. Secondly, using organic fertilizers requires microbial activity to breakdown the nutrients for the plant's use. These populations will go through "boom and bust" cycles, as Al says, and as a result the nutrients may not always be available in proper abundance. Lastly, organics will hasten the breakdown of the mix, compromising durability, another great benefit of the mix.


  • huanle0

    Thanks Josh.....this is a valuable post (lesson) for me to learn. AWSOME.

    I am just in the process of trying to learn how to grow and care for containerized JMs.

    So as for the fertilizer goes, the FP 936 should be good....just give it a little when it is leafing out in early spring, right...!

  • PRO

    I fertilize with FP 9-3-6 right up until the point in time I'm forced to bring my maples in to avoid the potential for killing low temps. In spring, I withhold fertilizer from maples I'm developing until the summer solstice. Maples have a habit of bearing the first pair of leaves on an emerging branch after a short internode. The next internode is typically VERY long - many times as long as the first one. In order to keep trees compact, you should eliminate trifurcations in favor of bifurcations, and pinch the central leader out of the first pair of leaves as soon as you can tease the leaves apart to get at it.

    Elimination trifurcations:

    Pinching the central leaders:

    Note how short the internode is between the new pair of leaves and the lower order branch. Sans pruning, the next internode could be as long as 10" or more - long enough to do serious damage to eye appeal. After the pinch above, the tree will produce 2 new branches, one from each leaf axil. because it's a NEW branch, the first internode will be VERY short. To produce a full and compact tree, you should be pinching religiously.


  • huanle0

    WOW...this is great Al....I am sure this technique would make the tree looks beautiful.....thanks again.

    But for me I always scare of to do heavy pruning. Just afraid of killing the tree...LOL . I may have to try next year.

  • Mauricio

    Hi everyone,

    The peat I was able to buy has already been pH adjusted. Do I still need to add garden lime because of the pine bark fines? I bought a pH meter online and am waiting for it to arrive so I can be sure, but I'm curious.

  • greenman28 NorCal 7b/8a

    Mauricio, yes add the Dolomitic Garden Lime for the pine bark. I suppose you could add just a little less.


  • gardengal48 (PNW Z8/9)

    The trees I grow in containers - mostly Japanese maples and dwarf conifers - tend to be those that prefer acidic soil conditions so I do not add lime to my mixes. However, my experience with containerized plants is that the pH of the mix is not nearly as critical as it is with inground plantings as fertilization offsets much of the shortcomings of a less than ideal pH.

  • greenman28 NorCal 7b/8a

    Oh, yeah, that's right, growing Japanese maples. I have multiple maples in mixes without the Lime. I've even grown maples in pure bark with Osmocote.


  • huanle0

    Hello all again,

    When making 511 mix, do I have to screen the pine bark ?

    I was only able to locate a small nuggets pine bark in my area. The size look aprroximatly 3/4".

    For Gritty mix, I think I am going to use Repti bark (Fir) as a substitution for pine.

    Thanks again

  • PRO

    3/4" is much too large: Ideal size range for 5:1:1 is dust to 3/8; for the gritty mix, use 1/8-1/4 if using fir, and 1/8-3/8 (nothing finer than 1/8) if using pine bark.

    Items, pencil, black sunflower seeds, .177" lead pellet, are to help with a sense of size.


  • newhostalady Z6 ON, Canada

    I would really like to understand what happens when one uses bark pieces that are larger than recommended for the 5:1:1 mix. I am guessing that the media cannot hold as much water and it drains too fast? Air pockets too big?

  • Andi C

    cation exchange capaicty also changes with pine bark size. the degree to which growth is affected likely depends on what you’re growing

  • newhostalady Z6 ON, Canada

    I want to grow hosta in 5:1:1 but am having difficulty finding the bark size required. So Andi you believe that CEC changes with bark size. Let's clarify what CEC stands for.

    Wikipedia says:

    "Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces.[1] Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water.[2] This is one of the ways that solid materials in soil alter the chemistry of the soil. CEC affects many aspects of soil chemistry, and is used as a measure of soil fertility, as it indicates the capacity of the soil to retain several nutrients (e.g. K+, NH4+, Ca2+) in plant-available form. It also indicates the capacity to retain pollutant cations (e.g. Pb2+)."

  • PRO

    I am guessing that the media cannot hold as much water and it drains too fast? Correct. Air pockets too big? Again, correct.

    CEC is a factor in that it increases as particle size decreases, but since growing in containers is much closer to hydroponic growing than growing in the earth, it's not as significant a factor as it would be if we were talking garden soil as opposed to container media.


  • newhostalady Z6 ON, Canada

    So if the bark is too large the water drains too quickly. That means the roots which are thirsty become very happy to feel the water trickling through the media only to find the water has gone by too quickly. Therefore the plant is still thirsty and the bark and peat have not been able to absorb some of the moisture? And then the bark and peat become rather dry? In time the bark and peat will not hold as much water as it could and the plant will continuously be thirsty? And if air pockets are too big, then that affects the PWT? Or if the air pockets are too large, does this just help to dry out the roots even more?

  • mblan13

    I like to think of it as humidity retention, rather that water retention. You do not want little pockets of water (a PWT) but you want the "air" spaces to be close to 100% humidity and the medium having soaked up enough moisture to be able to keep the humidity in those pores as high as possible. If the air pockets are too large, they might drop to, say 50% humidity. The roots will start to dry out and die off.

  • tropicofcancer (6b SW-PA)

    Air spaces between particles and water retention are closely related. Water exists in soil as a thin film around particles and for porous particles as absorbed water. Larger particles have less surface area and more air space. As the particle size is decreased, air space decreases and surface area of particles increases and so does the amount of water clinging to the surface. The trick is to hit the right balance between water retention and air spaces.

    When air spaces are sufficiently small capillary action of water kicks in. Water clinging to particles acquire a tendency to move against gravity. You can see that with a dry sponge when placed in dish with a layer of water. This tendency of water to rise up is what leads to PWT. PWT is the bottom portion of soil that is saturated with water. That is the air spaces are also filled with water. 511 does not eliminate it completely but reduces it drastically while keeping the overall water retention high enough.

    Above the PWT the air spaces are high humidity environments as mblan said.

  • newhostalady Z6 ON, Canada

    Great explanation mblan13 and tropic of cancer!

  • newhostalady Z6 ON, Canada

    " Ideal size range for 5:1:1 is dust to 3/8"

    Does that mean you can use bark which is all dust, or all 3/8" pieces, or any combination of bark in those sizes when making a batch of 5:1:1?

  • tropicofcancer (6b SW-PA)

    No you cannot use all dust - it will have very high PWT - means saturated with water with no air space. Just like a fine sponge. Remember that thin layer of water on particles I talked about before? The small particles will have large surface area to support that thin layer of water and capillary forces will be very high pushing water through those minute air spaces making them saturated. Opposite is true for all large particles - lots of air spaces and very little water holding capacity.

    Imagine a bottle filled with say 3/8 inch diameter marbles. There will be lots of air spaces between the marbles. In fact too big air spaces. Now add a bunch of smaller marbles that exactly fit the air spaces in between the marbles. This will reduce the gaps between marbles considerably, right. Now add some marbles that fit exactly in those air spaces - and so on.

    To get an idea how it works here is an image found on wikipedia to illustrate:

    So to reduce the air space you need smaller marbles and each time you do that that thin layer of water on particles come closer. If they are too close capillary action will draw water up through those spaces.

    Notice how you need more of the smaller particles to pack in between. Actually, the volume of the larger ones is larger but the number is smaller. As you get smaller in size the volume needed is smaller but the number of particles is larger.

    So what is the right proportion - hard to tell and hard to control. I normally sift out anything below 1/8 inch first. Then add about some back so that it is about 15% by volume of the total mix.

  • newhostalady Z6 ON, Canada

    Thanks for taking the time to explain in more detail. It is really helping me, and I think others, to understand what happens in different sized media. Great image you found there to demonstrate.

  • tropicofcancer (6b SW-PA)

    My example is a simplification using an ideal scenario but helps to explain. Reality tends to be different.

    For one, bark is essentially flattish (fir bark is less so) and has a tendency to lay flat on each other. This effectively makes it quite a compact stack with much less air space - called stratification. Here is where more spherical particles like perlite/pumice/turface plays a big role in preventing that stacking and encouraging more random orientation of the bark in the mix.

    If you search for circle/sphere packing you will find it is a hot research topic. That is how I got the image. Nothing much to do with soil though. It is important in inventing exotic materials and a mathematical curiosity.

  • newhostalady Z6 ON, Canada

    I understand. Your explanation is a simplified version. I think that is the best way for new people (like me) to understand these concepts. You start off simple and then move on to more complex principles.

    It's wonderful that you have taken your time to explain the above for me and others interested.

  • mblan13

    Another example would be in bonsai soil. High mountain pines require less water than lowland species and deciduous trees like Japanese maples that grow in soil, rather than little pockets of organic matter in rock crevasses.

    So when potting a mountain pine it's recommended to use 1/4 to 3/8 inch particles, but for lowland species they will recommend 1/8 to 1/4 and ones that do better in very moist soil 1/16 to 1/8.

    So the smaller the soil particulate the more water it will hold.

  • mblan13

    I like to use Bonsai soil as an example. High mountain pines that require less water get a soil that consists of 1/4 to 3/8 particles, lowland pines or deciduous 1/8 to 1/4, and ones that like wetter soils 1/16 to 1/8. So the smaller the particles, the more water they will retain...Easy Peasy!

  • Vladimir (Zone 6a Massachusetts)

    Tropic. Regarding the proportion of pine bark dust, it varies from lot to lot and depends on how long the mulch has been lying around and so is quite variable.

    I normally sift out anything below 1/8 inch first. Then add about some back so that it is about 15% by volume of the total mix.

    I have been trying to get this information from Al but he has evaded answering my question.

  • tropicofcancer (6b SW-PA)

    Vladimir: That is the reason I sift out 1/8 or less (call it fines) first and mix it back in controlled quantity. If the bark looks out of proportion on the high side I will also sift out greater than 1/4 and mix back some of the 1/4-1/2 (call it chunks) back for 511. I wish I had a 3/8 screen. Having done this for quite a while I mostly eyeball it. When repotting if I feel I need to adjust for a particular plant I use bark fines, bark chunks and perlite to adjust it a bit. I treat the original recipe as starting concept and play around with it.

  • newhostalady Z6 ON, Canada

    "So the smaller the particles, the more water they will retain...Easy Peasy!"

    I have rooted some coleus in water. I do have some smaller bark sizes like 1/16 to 1/8th. And I think coleus like their water. So potting them using the smaller bark pieces in 5:1:1 will make for a media that will retain more water? I also read somewhere in the forum that the addition of turface increases water retention. The ratio being 5:1:1 plus 1 of turface. True?

  • PRO

    Vlad - do you think claiming I'm evading you and donning the mantle of victim as a result my sloth for not ensuring you have an understanding of the nuances associated with soil science is an appropriate way of venting your frustration? My brother, also my partner, is dying. That comes with a lot of emotional freight, and it essentially doubles my work load to the point I'm presently working 60 or more hours every week. Helping folks on the forums is an uplifting part of my personal growing experience; but simply put, it's more uplifting to share with people who don't chide me, as you've done on numerous occasions, because they feel entitled to attention I'm sometimes unable to provide.

    If/when you've gained a working understanding of the concept that drives water retention, you won't have need to ask these questions over and over because the answers will become obvious. You've been around these forums for a good long time - far longer than what would normally be required to gain an understanding of what drives water retention. Except where I think my replies might be of value to others who might be following the thread, I'm probably going to let someone else field your questions because there isn't much I can do to help you, lacking the basics. If you're unable to understand the concept, it's not going to do good in any measure if I repeat answers to the same questions from the same person in audio-loop fashion.

    NHL - I think what you suggest is something of an over-simplification. If we except cacti and succulent aficionados, probably 90-95% of the plants we most commonly grow in containers all prefer roughly the same type of environment for their roots. They want a soil with particles large enough that limiting amounts of water do not collect in the spaces between particles. It may seem perfectly reasonable to assume some plants LIKE moisture more than others, but in most cases, it's more accurate that some plants TOLERATE high moisture levels better than others.

    Smaller particles have the POTENTIAL to hold more water than larger particles, but picture in your mind's eye a jar of BBs, and a jar of Turface, Calcined DE, Pumice, or perlite that consists of particles twice the size of BBs. Which holds more water - the BBs or the other materials?

    Where soil particles are uniform in size, soils start to retain perched water as particle size diminishes to something less than .100" (1/10 of 1"). The smaller the particles become, the greater the potential for water retention. The smaller the volume of perched water a soil holds, the greater the potential for maximized root health. A worthy goal to work toward for most plantings is a soil that maximizes water retention while minimizing perched water's presence. This is accomplished by having a high % of internally porous particles in the size range of 1/10 to only slightly larger. In a perfect world, it would be particles .100-.125, but unless you have unlimited supplies and don't mind screening, this isn't realistic enough to make large numbers of growers interested in experimenting with highly aerated soils that hold little to no PW.


  • Vladimir (Zone 6a Massachusetts)

    Oh well, I give up trying to get an answer.

    I am truly sorry that your brother is dying and the difficult time you are having now. I know what it is like. Al, I wish you the best.

  • tropicofcancer (6b SW-PA)

    newhostalady: Coleus will be perfectly fine in 511. In early summer I directly root them in 511. In fact I root everything in 511. At the most I would sprinkle a thin layer of turface or bark fines, whichever is handy, on top of the mix for small cuttings.

  • newhostalady Z6 ON, Canada

    To Al:

    "Smaller particles have the POTENTIAL to hold more water than larger particles, but picture in your mind's eye a jar of BBs, and a jar of Turface, Calcined DE, Pumice, or perlite that consists of particles twice the size of BBs. Which holds more water - the BBs or the other materials?"

    The BBs!

    So here is what I understand:

    If the particles in a potting media are less than 1/10th of an inch, one will have a higher perched water table. This potting media will hold a lot of water. This will not be beneficial to the potted plant as the water will, in turn, rot roots and not allow a good supply of oxygen to the roots. So the goal would be to have a media that is 1/10th of an inch or slightly larger. This container media would maximize water retention but have the lowest perched water level possible. So the goal would be to have POROUS particles in the .100 to .125th size (of an inch)---or at least as close to that as possible---to give your container plants the best chance of health plant and root development!

    I hope I've got it! Thanks Al!

    Tropicofcancer, thanks for the information. I did root some coleus recently. I put some in water and some directly in potting medium. I bet 5:1:1 would have been a much better choice! Not sure the role of the turface or bark fines on top.

  • tropicofcancer (6b SW-PA)

    Turface or bark fines on top help to prevent the top drying out too quickly while the cuttings are rooting. Same is helpful when sprouting small seeds in 511.

  • newhostalady Z6 ON, Canada

    Great info. Going to make a note of that so I don't forget!

  • Conrad Todd

    Where do you guys get your bark at, and what is the name of the brand and size of the bark chunks, such as mini bark etc.? Also do you end up having to shift out a lot still or is it for the most part the right size when you get it? Thank you for your time guys.

  • newhostalady Z6 ON, Canada

    You might find this link helpful:

    Supplies by State/Region: Al's Gritty Mix

    It is helpful if you add the area you are from along with your name. Also best if you start your own thread. You may get more responses that way.

  • stuartlawrence (7b L.I. NY)

    Conrad Todd, I get my bark from Agways. Go to their website here and see if you have an Agway near you where you can order and buy it.

  • Dennis

    Could someone help me understand this portion:

    /quote/ There will be a naturally occurring "perched water table" (PWT) in containers when soil particulate size is under about .125 (1/8) inch, so best would be particulates in the 1/16 - 3/16 size range with the 1/16-1/8 size range favored. /quote/

    Shouldn’t larger particles be favored, hence the preferred size range should be LARGER than 1/8 inch (instead of 1/16-1/8)??

    Edit: Ahh! Got it now! I realise 1/16-1/8 inch is for 5/1/1 and not 1/1/1...

Need help with an existing Houzz order? Call 1-800-368-4268 (Mon-Sun).