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A Soil Discussion II

tapla
11 years ago

A previous thread on the same subject had topped out at the limit of 150 posts. In case there is additional discussion or more questions, we can continue here. The text repeated:

A Soil Discussionsize>

Ive been thinking about what I want to say about soils here, and how I should open. IÂm going to talk a little about soils primarily from the perspective of what is best for the plant - not the planter. ;o) More often than not, the two ideas are mutually exclusive, and the plant suffers loss of vitality for grower convenience. There is absolutely nothing wrong with that. Probably none of us can afford the time it would take to give our plants the best care possible, and we need to decide on an individual basis, how much attention we can pay our plants. IÂll explain later.

Let me start by saying that whenever I say Âplants I mean a very high % of house plants and freely allow that there are exceptions to every rule; but, we need to learn the rules before we can recognize the exception. IÂm going to offer a few (of what I think are) rules I believe are difficult to challenge, and that IÂve adopted in my growing practices after a fair amount of study and consideration. IÂm going to leave light levels out of this conversation after acknowledging that they are probably just as important as soil to a planting, the difference being, we can recognize and change poor light levels easily if we choose, but poor soils are not so easily remedied.

Rule: Plants need air in the root zone as much as they need light and water. The soils we usually buy in a bag either do not supply enough aeration from the outset, or they do not supply it for a long enough period. Most, or at least many readers are expecting their plants to live in the same soil for several years, when the fact is that most peat based soils substantially collapse within a single growth cycle. That is to say that the peat particles break down into continually smaller pieces. This reduces the number of macropores (large air pockets), causes compaction, and increases the amount of water the soil holds in root zone and increases the length of time it remains there.

What does this mean to our plants? Well, there is the specter of root rot, but even if we set that aside, there is something more subtle occurring. Whenever roots are deprived of oxygen (O2) they soon begin to die - incrementally. First, and after only a few hours in saturated conditions, the finest roots that absorb water and nutrients begin to die. Already, the plant is operating under stress. Gradually, thicker roots die unless the plant uses the water in the root zone or it evaporates and O2 is allowed back into the soil. When adequate aeration is restored, the plant is disadvantaged, because fine rootage has died. The plant begins to regenerate the lost roots, but guess what? It has to call on energy reserves it has stored because the roots cannot efficiently take up water and the building blocks from which it makes food (nutrients/fertilizer). This stored photosynthate that goes to root regeneration would have been used to increase biomass - flowers, fruit, foliage, stem thickness. See how subtly aeration affects growth?

Rule: Our number one priority when establishing a planting should be to choose a soil that guarantees adequate aeration for the expected life of that planting. We can easily change every other cultural influence if we choose. Light, temperature, nutrients, moisture levels Â.. all can be changed, but we cannot change aeration, so we really need to consider that as a priority.

It is here where we need to bring attention to the fact that, as alluded to above, convenience has costs. IÂm not saying that in chiding fashion. I simply want to make the point that when youÂre able to go several days to a week without watering, in a high % of cases, the cyclic death and regeneration of roots is taking place. The plant is growing under stress and is weakened to varying degrees, depending on the severity of O2 deprivation in the root zone.

Rule: A fast soil that drains freely will be far superior from a plant vitality perspective than a more convenient soil that stays wet. The cost: YouÂll need to decide if youÂre willing to water and fertilize more frequently to secure the added vitality.

I could go on for days about soil, but IÂm hoping that IÂll be able to discuss HOW we can get to a better place with regard to our soils through answering any questions that might come up, and exploring options. Before I close, I would like to talk for a minute about another bane of poor soils.

Many of us recognize what we consider the main danger of overwatering - root rot, and do our best to prevent it. Most often, itÂs by watering sparingly so the soil is never saturated, but let me explain what happens when we do this.

Plants best take up water and the ions dissolved in it when the ion level is very low. This ion level is measured by either electrical conductivity (EC) or the total amount of dissolved solids (TDS). Problems arise when the TDS/EC level is low, when the plant can take up water easily. It remains hydrated, but starves because there is not a high enough concentration of ions in the soil water. If the level of TDS/EC is too high, the process of osmosis is affected, and the plant cannot efficiently take up either water OR nutrients, and the plant can starve or die of thirst in a sea of plenty. ItÂs up to us to supply the right mix of all the nutrients in a favorable range of TDS/EC.

IÂm sorry to be a little technical, but IÂm getting to a point. When using soils that are not fast enough to allow us to water copiously and continually flush the salts that accumulate from fertilizer and irrigation water something unwanted occurs. If we do not flush the soil, these salts accumulate. This pushes up the level of TDS/EC and makes it increasingly difficult for the plant to take up water and nutrients.

Imagine: A soil that is killing our most efficient roots, which stresses the plant and makes it more difficult to take up water due to the lack of those roots, while it insures that the level of TDS/EC will rise, making it difficult or impossible on yet another front for the plant to take up water and nutrients. Is it any wonder that our plants start to struggle so mightily toward winterÂs end? Are we really seeing the effects of low humidity or do you think it might be drought stress brought on by either an inappropriate soil or less than favorable watering practices? Probably a little or a lot of both.

Rule: Whenever you consider a plant in trouble, you must consider not only the plant, but the rest of the planting as well - including the soil. The insect infestations, diseases, and stress/strain we so often need help with here, can almost always be traced back to weakening of the organism due to an inappropriate soil (or, as noted, inadequate light - though in an extremely high % of cases, it is indeed the soil).

This only touches on the cause/effect relationship of the soil to the planting. If there are questions, IÂll try to answer them. If there is disagreement on a point or points, IÂll offer the science behind my thinking and you can decide individually if the things I set down make sense.

I would strongly urge anyone who wasnÂt long ago bored to tears to follow this link to another thread I offered on the container gardening forum. If you want to get into the science and physics of what happens to Water in Container Soils

, follow the embedded link. You'll also come away with the knowledge of what makes a good soil.

I hope this starts a lively discussion and provokes lots of questions, but more importantly, I hope it eventually, and as the thread progresses, helps put a few more pieces of the puzzle together for at least a few forum participants. ;o)

Al

Click here to link to previous thread

Comments (60)

  • Yoly Garcia
    3 years ago

    This discussion has been an eye opener for me, and to think that the search that brought me here was something like. "How to keep zee zee plants happy?" LOL. Yep I'm a novice at this, but I've learned so much in the last 2 hours I spent reading through this discussion that my head feels like it's gonna start smoking any second now. Please pardon the the long introduction, I'll get right to the question, All of my potted plants are now planted in miracle grow potting mix (I know, what a shame. ) so I want to change all of them to the TGB mix, How should I do it, I'm afraid that my plants are going to get shocked with the change. Is there a proper way to do it?

    Secondly I have a little indoor herb garden would the TGB mix work for that too?

    Many thanks .

    tapla thanked Yoly Garcia
    Best Answer
  • tapla
    Original Author
    11 years ago
    last modified: 5 years ago

    Great job! I think you'll be really pleased when you get used to this soil. Look how much it looks like mine:

    {{gwi:53827}}


    ". . . should I be applying the fert and supplement at full strength per the bag instructions or should I be diluting it?"

    With that soil, if you watered copiously, you COULD fertilize at the full recommended strength every other time you water. I'm not suggesting that you do, only making the point that you COULD, w/o worry of burn. The reason you could is because you'll be flushing the old salts from the soil each time you water.

    Keeping the fertilizer load always at luxury levels has some drawbacks, so you should try to keep the supply of nutrients at adequacy levels. As long as you are watering so a good amount of water exits the drain at each watering, I would start out with one of these programs: A) Fertilize with a 1/8 strength solution at every watering B) use a 1/4 strength solution every 3rd or fourth time you water C) use a 1/2 strength solution every 2 weeks. Since all my plants are outside in the summer, I sort of use a combination of these programs based on current growth rate, temperature, watering frequency, etc.

    ". . . do you have to water more frequently in the 1-1-1 mix? How many times a week would you suggest?"

    Yes, you'll almost certainly need to water much more frequently than you're used to if you were using a bagged soil. Even though it's very difficult to over-water this soil, you can if you work at it, so do not water on a schedule - water as needed. Different containers will have different intervals between watering.
    Until you get used to the soil, I would put a wick in the drain hole. It will drain any perched water if you DO over-water, and it can be very helpful in deciding when you should water. If the wick is wet - wait. Once the roots colonize the whole container, just remove the wick to increase the intervals between watering. Slick, huh?

    ". . . here's a pic of the dieffenbachia I'm trying to save. I had to butcher it to get rid of the rotting leaves. Do you think it can recover?"

    I'll bet on it. ;o) It looks like there is some leaf deformity in it, which looks like a Ca deficiency - prolly caused by the anaerobic root conditions. Plants need a continuous supply of Ca, so anything that interrupts the nutrient stream in a plant can cause a Ca deficiency. You were light on the lime @ 1 tsp per gallon, but if the fertilizer or micro supplement you're using contains Ca and Mg, you'll be fine. Let me know if they are lacking either.

    I hope you removed most (all is prolly too much to hope for) ;o) of the soil and trimmed any rotted roots from the diff? The plant will recover much faster if the soil in the container is uniform. If you didn't, I would chop (scissors) the bottom half of the root mass right off & clean the soil off the roots & repot. You can start fertilizing right away - no need to wait.

    I don't know if you can tell, but I'm really excited for you. I think you'll never look back. ;o)

    Al


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  • gary30mazak
    11 years ago
    last modified: 5 years ago

    When I repotted the dieff I did not cut any of the roots away but i did gently rinse off 99% of the old soil under lukewarm water under the faucet. The roots didnt look to bad to me besides the surprising lack of them. I thought a plant that size would have a big rootball, but not this one. Do you think I should cut them anyway? Also I made a typing mistake about the lime. I added 1 tbsp. not 1 tsp.
    And here is the analysis of my fert and micro supplement.


    Peters Excel 15-5-15 Cal Mag

    total nitrogen- 15%
    available phosphate- 5%
    soluble potash- 15%
    calcium- 5%
    magnesium- 2%
    boron- 0.015%
    copper- 0.007%
    iron- 0.075%
    manganese- 0.037%
    molybdenum- 0.007%
    zinc- 0.040%

    Bio Genesis Mineral Matrix Micro-Nutrient Supplement 0-0-1

    soluble potash- 1.0%
    magnesium- 0.5%
    sulfur- 3.0%
    boron- 0.02%
    copper- 0.05%
    iron- 2.0%
    manganese- 2.0%
    molybdenum- 0.0005%
    zinc- 3.0%

  • tapla
    Original Author
    11 years ago
    last modified: 5 years ago

    It's hard to tell about the roots w/o seeing them, so I prolly shouldn't offer advice. I would prolly lean toward reducing the roots so they go into the pot in a very tidy and sort of flat arrangement. If I thought the roots would not be able to support the foliage, I would reduce the foliage by cutting the leaves in half across the veins. Later, when the plant has recovered, I would just snip off the butchered leaves.

    The butchered leaves make me think of something I encounter frequently. It's just an aside, and not directed toward you, Gary. Some people have certain ends in mind when they grow their plants, and I often need to remind myself that what we expect/want from our plants are different. Some people regard them as decorations, and when they begin to decline, they toss & get something different, or another of the same - the "revolving door attitude." Some equate maximum growth with health. They WANT the plant to grow big as fast as they can push it, but then they often wonder what to do with it. In other forums, I see people that want their potted fruit trees to produce a bumper crop every year - even though the stress can often jeopardize the life of the plant. Anyway, there are other different ways of looking at plants that I don't mention, because my only point was that different people DO have different expectations of their plant material. The reason for bringing that up, was the idea that I would, w/o a second thought, just reduce the roots and cut the leaves in half. ;o)

    My way of looking at plant material is to first keep it vital and robust (healthy and growing well), and second - enjoy its appearance; or, I'll gladly sacrifice its appearance temporarily to insure its health. How many people look pretty while in intensive care? ;o) My perception is the greater number of people I talk with on the forums don't look at plant material that way, so when I suggest something like chopping at the roots or cutting the plant back hard to rejuvenate it, they're often aghast & think I'm nutts (2 't's means xtra nutts). ;o)

    I think you could shelf the Bio Genesis if you're using the Excel. It really doesn't offer anything your fertilizer doesn't already have, except sulfur (S) and the line between deficiency and toxicity, when it comes to micronutrients, is fine. Since S is often in short supply in container soils, you should probably think about a source. The ratio of Ca:Mg is best at around 4:1. The Excel has it at 2.5:1, so you could still afford to add a little more Ca. Adding a teaspoon of gypsum (calcium sulfate - very inexpensive) per gallon of soil will supply additional Ca AND S. You could also add a teaspoon of elemental/agricultural/garden sulfur to each gallon of soil to cover the S requirement. I just don't think that simply because it supplies S, there is sufficient reason to duplicate the other nutrients by using the Bio Genesis.

    Al

  • tapla
    Original Author
    11 years ago
    last modified: 5 years ago

    Gary - to clarify something: You already have lime in the batch of soil you made, so what I said above doesn't apply to that batch - only future mixes that you intend to use the Excel with. You would eliminate the tablespoon of lime from the mix and substitute 1 teaspoon of gypsum in its place. I bet if you look at the analysis of the Excel, most of the N comes from nitrate and not in ammoniacal form. This allows the manufacturer to add Ca and Mg compounds that normally fall (precipitate) out of solution with high % of ammoniacal N. IOW - it's sort of unusual for soluble fertilizers to contain Ca and Mg, so if you're using a fertilizer that contains those elements, you need to tweak the rest of the additives to compensate. Sorry if that makes trouble for you, but once you grasp the concept, it's really easy. ;o)

    Al

  • gary30mazak
    11 years ago
    last modified: 5 years ago

    well I pulled the plant and cut about 1/3 the roots off and repotted in the same soil just top dressed. I watered it and added no additional fert, I fertilized it full strength yesterday. So you are saying in my future mixes to axe the lime and micro-nutrient and add a teaspoon of gypsum per gallon? I have 25 lbs of the excel so I will be using it for a while LOL!! Can gypsum be found at HD or lowes? Here are a few pics of the dieff after I cut it. thanks again Al.

    {{gwi:99648}}


    {{gwi:99649}}


    {{gwi:99650}}

  • tapla
    Original Author
    11 years ago
    last modified: 5 years ago

    "So you are saying in my future mixes to axe the lime and micro-nutrient and add a teaspoon of gypsum per gallon?"

    Yes. Because you are using a somewhat unusual soluble fertilizer, in that it contains all the nutrients (except S), including both Ca & Mg, you don't need lime. The ratio of Ca to Mg is ideal at about 4:1, but your fertilizer provides it at 2.5:1. This means that you could stand a little additional Ca. Gypsum contains both Ca and S, so you can kill 2 birds by adding a small amount to your soil, bringing up the Ca ratio AND providing the missing S. Got that? ;o)

    "Can gypsum be found at HD or lowes?"

    They do sell it, but it might be a seasonal item. If they have it, it will be near the fertilizers in 50 lb bags, which should hold you until somewhere around the time that your great great grand children are just starting to think about a final resting place. Espoma packages it in 5 lb and 38 lb bags. The 5 lb bag of their product will cost almost as much as 50 lbs of generic, but there's prolly something to be said about the blessings of not saddling your great great progeny with the extra 45 lbs.

    The roots look great. Put your diff outdoors in full shade that has open sky above (north side of a fence, or building w/no overhang) if you have a spot like that, for quickest recovery.

    Al

  • tapla
    Original Author
    9 years ago
    last modified: 5 years ago

    Posted by jillalameda 9 (Sunset 16/17) (My Page) on Sat, Aug 28, 10 at 12:41

    (Since the other post had (supposedly) topped out at 150 posts, but Jill was able to sneak an extra in, I had to copy/paste the reply here to answer.)

    "If you're still out there, I have a question. Please forgive me if it's answered above; there are well over 100 posts and I only read through the first 20 or 30.
    Would adding decomposed granite improve bagged potting mix? If so, what proportion would you recommend?"

    It could, if you added enough, but there are a lot of qualifiers that need to be considered. First, it would have to be screened to a size that was in a range from just under 1/8" to around 3/16", and there would need to be a significant fraction of granite. In fact, it would have to be the largest fraction of the soil.

    Adding 'some' DG to a heavy soil doesn't change the drainage characteristics of the soil or the height of the PWT. To visualize this, think of how well a pot full of BBs would drain, then think of how poorly a pot full of pudding would drain. Even mixing the pudding and BBs together 1:1 in a third pot yields a mix that retains the drainage characteristics and PWT height of the pudding. It's only after the BBs become the largest fraction of the mix (60-75%) that drainage & PWT height begins to improve; and so it would be if you added the DG.

    You cannot add coarse material to fine material and improve drainage & the ht of the PWT. Use the same example as above & replace the pudding with play sand - same results. The benefit in adding DG or perlite to heavy (water-retentive) soils doesn't come from the fact that they drain better. The fine particles simply 'fill in' around the DG or perlite, so drainage & the ht of the PWT remains the same. All the DG or perlite does in heavy soils is occupy space that would otherwise be full of water. The DG or perlite simply reduces the amount of water a soil is capable of holding because it is not internally porous.

    If you want to find advantage in a soil that offers superior drainage and aeration, you need to build it into the soil from the start, by ensuring that the soil is primarily comprised of particles much larger than those in peat/compost/coir. The soils I recommend either have a 2/3 fraction of inorganic particles around 1/8" in size (it's no accident this is the size I chose - the PWT is reduced as soil particle size increases, until it disappears entirely as soil particle size reaches just under 1/8"), plus a 1/3 fraction of conifer bark about the same size or a little larger; or they are made beginning with a large fraction of pine bark so drainage and aeration are inherent from the beginning, so we're not trying to amend soils to add these valuable properties as an afterthought.

    Getting back to your question directly - You would have to add enough DG of a favorable size so that the DG was about 60-75% of the o/a mix to ensure good drainage and a reduced PWT height. The problem here is, that now you've sacrificed a LOT of your water retention. Better, would be to use half screened Turface or calcined DE (diatomaceous earth) and half of the DG to make up that large fraction(60-75%). This would ensure both drainage and aeration, while increasing water retention to more acceptable levels. Essentially, we're almost talking about the gritty mix here. If you replaced the soil you have with pine bark, it WOULD be the gritty mix.

    I would encourage you to try a soil that is durable and based on pine bark, or better still - a soil like the gritty mix. They will make your job easier and likely increase your effort:reward ratio. They also offer a significantly wider margin for grower error, compared to heavier and more water-retentive soils.

    Al

  • gravyboots
    9 years ago
    last modified: 5 years ago

    Wow! What a fascinating discussion & so much info! This thread is the one that pushed me to join...

    So, onto my question: it is now mid-Sept - should I wait until spring to try an airier soil for my houseplants? I think trees grow roots in winter & vegetation in summer, so if house plants are the same (& why wouldn't they be?), it seems to me they'd appreciate an airier soil now... but then I wonder if they'd have a longer recovery in cooler temps & lower light.
    I do have about 25' of southern exposure windows, if that makes any difference. My house is also large, old & drafty, with single-pane windows & wood heat. The plants don't live in the same room as the stove, so certainly they're cooler (high 50's to mid 60's) & maybe the air is not quite as dry...

    Anyhoo, this summer I potted up a largish, distressed rubber tree from severely hydrophobic soil, a pot-bound dracena pair & a whacked, 1-stem (cutting saved from trash 5 yrs ago) schefflera. I used chunky (screened through 1/2" mesh), mature compost from my pile & as always, filled the bottom 1"-2" of the pots with circus-peanut (y'know, the orange ones) sized rocks for drainage. I did not trim any roots, but was a bit rough with them, so there was some breakage, just not to the extent of a hearty trim. The compost is certainly faster than the previous soil, but surely nothing like your creation.

    Should I repot now? And trim roots? Or should I wait? I am in Western Washington, by the way...
    Thanks so much for all the excellent information you provide!

    PS - I know this post is already pretty long, but I wonder about a soil compromise? The largely inorganic mix you describe, with 1/2" to 1" mature compost atop? Might the small particles filter into the chunks & extend my watering by a day or two? Or, is it just a bad idea...
    OK, thanks again!!

  • tapla
    Original Author
    9 years ago
    last modified: 5 years ago

    Hi, GB. Thanks for the nice compliment. I'll touch lightly on several areas. Feel free to respond with questions or comments.

    What I write and how I grow comes from the perspective that the most important choice you'll make when establishing a planting is the soil, and the most important property a soil can have is good aeration/drainage for the intended life of the planting, which is why the soils I use are made from particles that either don't break down at all, or break down very slowly.

    Some soils are a hodgepodge of ingredients mixed with hope, and others are built as simply as possible around desirable physical characteristics, the ingredients being selected because they contribute to the soil in more than 1 way. That's the type of soil the gritty mix is. Making alterations to it w/o a good understanding of how/why the soil works so well in the first place, and not understanding the impact that particular alterations would have on the soil, will more than likely leave you growing in something closer to what you're trying to get away from, than what you are trying to move toward.

    Drainage layers don't improve drainage or reduce the height of the perched water table, but they CAN reduce the volume of water in the perched water table. If you don't understand that phrase, you'll find an even more thorough discussion about container soils if you click on the link.

    Now is not a good time to repot tropical or subtropical plants. For fastest recovery and minimal risk of insect infestation/disease due to a weakened plant, repot healthy plants in the month prior to their most robust growth. That would be Jun or Jul for you. You would be best served if you pot up root bound plants into a soil similar to what they are already in, and nurse the plants through the winter by watering carefully & flushing the soil thoroughly several times before summer - unless you have good supplemental lighting, in which case you could get away with repotting now.

    Al

  • gravyboots
    9 years ago
    last modified: 5 years ago

    thanks for such a prompt reply Al!

    I'll leave everyone alone for now...

    You mentioned potting into a similar soil; that would be necessary only if the plant were distressed & urgently in need of potting? It's OK to move to a different type of medium if I wait until late spring/early summer?
    None of my plants are in such dire straights currently. Except that hylocereus I just inherited from my sister-in-law who moved out of state; it appears to be in ancient standard potting mix - would it be better off staying as-is with light applications of Schultz Instant through the winter?

    I think I will try the turface/granite/bark mix. In the meantime, I'll keep (re)reading these soil threads... the idea of making soil with a purpose is very interesting & it's about time it dawned on me :) duh.
    I'm not an active fertilizor, so I've always potted the houseplants in soil I thought would feed them. Although, since most of my plants are over 10 years old - some as old as 20 (a begonia, an aloe & a little phil) I can't be too hard on my self for being a late bloomer when it comes to soil! But, as you mentioned in an earlier post, surviving and thriving are not the same...

  • tapla
    Original Author
    9 years ago
    last modified: 5 years ago

    There is no need to feel you're intruding or being a bother, Boots. An open mind and someone who wants to learn makes for rewards running in both directions.

    If your plant is obviously in jeopardy of dying over winter because it's horribly root bound, it's better to do something to mitigate the stress. First choice would be to make multiple vertical cuts in the root mass and only pot up into a similar soil temporarily. Second would be a repot, but I wouldn't recommend it unless there was something more than tight roots at work. You can do a full repot, which includes bare-rooting and root pruning (if applicable), next year after the plant(s) have gained some energy reserves.

    I would learn how to flush the soil and do it regularly, until you can get your plants into a soil that allows you to water freely enough that salt build-up is not an issue. I'm guessing the fertilizer you're using is 10-15-10. Probably not the best choice for houseplants as your 'go to' fertilizer. No plants use more P than N, so supplying all the extra P just makes it more difficult (than necessary) for plants to absorb water and the nutrients dissolved in water. Excess P can also inhibit uptake of N, Fe, and Mn, as well as other micro-nutrients. It also unnecessarily raises pH. An acid forming fertilizer like MG 24-8-16 or 12-4-8 are better choices. I happen to use Foliage-Pro 9-3-6. It's an excellent choice as your all purpose fertilizer. It also supplies a large fraction of its N in nitrate form, which helps keep your plants from stretching out.

    It's not unusual that you don't know anything different than what you've always grown in. Very few hobby growers, other than the few who frequent a few forum sites where the topic is widely discussed, have any idea there are alternatives to bagged, peat-based soils. Hopefully you'll be impressed enough with what you learn and the testimony of others to try something different. If not, at least you'll have learned along the way what issues to watch out for and will have some ideas about what you're seeing and how to deal with them.

    Please DON'T be hard on yourself. Make it fun. The more effort you put into growing, the more you get out; but it's still up to you to set the parameters of the 'in' part.

    Al

  • gravyboots
    9 years ago
    last modified: 5 years ago

    oh! ha-ha-ha! by "everyone" I meant the plants at my house!

    Totally off topic:
    I did repot the hylocereus today, into a even mix of fine orchid bark, chunky compost, pumice, with some coir... I thought I'd have to break the old pot to get it out! There were random plastic items in the roots, as well as a large chunk of rotty stick & some other junk, so even though I didn't intend to do a total re-pot, it happened anyway. I did pot slightly up, mostly for stability - this is fair sized (still teeny by hylocereus standards, though) and the prior pot was about 4" wide by 8" tall = tippy; new one is the same height, but wider. It also got this plate-sized grow-through thingy on legs I noticed at the hardware store, so the limbs have some support.

    Several of the limbs are about 3' long, so hopefully it has what it needs to make it through the winter... a couple broke off, so they are suberizing, then I'll try to root them out. Less "mouths" to feed for winter, but a smaller food factory too. I think it will get to spend the winter in the room with the stove, as it will probably need the extra warmth.

    Yes, my fertilizer (once I actually found it! A mouse has apparently gnawed off the top of the dropper bulb) is a 10-15-10... but who knows when the last time I actually fertilized was?

    As for peat, I think that was the problem for the poor ficus!! The previous owner left a GIANT bag of it out by the compost bin, so I'm guessing he was really into peat. When I took it out of the pot, the roots were bone dry, even though LOTS of water had run through the pot. It was severely dehydrated due to that old, peaty soil, had dropped all of it's leaves & the ends were even starting to wither. It might get to spend the winter in the room with the stove too, although it is recovering surprisingly well.

    Thanks for the encouragement & will be checking out more of the houseplant discussions :)

  • tapla
    Original Author
    9 years ago
    last modified: 5 years ago

    Lol - I can see the meaning of 'everyone' now. ;o) Take care.

    Al

  • thesss
    9 years ago
    last modified: 5 years ago

    Hi Al,
    I just wanted to say thanks for starting the Soil Discussion threads and sharing really good information. It really helps us novices.
    I've gathered some information based on these threads and found another thread that lists some suppliers here in the Bay Area so hopefully I'll be able to start getting some materials this weekend. Some of my house plants are ready for a split or pot-up and I think I'm ready to use a better mix.
    Thanks again!
    -Thess

  • windeaux
    9 years ago
    last modified: 5 years ago

    Welcome forum registration, Thesss. Glad you finally decided to come aboard! :)

  • thesss
    9 years ago
    last modified: 5 years ago

    Thanks windeaux! :)
    -Thess

  • tapla
    Original Author
    9 years ago
    last modified: 5 years ago

    Hi, Thess. Welcome! .... and you're welcome. If you find you need any help, please don't hesitate to ask.

    Thanks for the kind words. ;o)

    Al

  • jodik_gw
    9 years ago
    last modified: 5 years ago

    I am amazed at all I have learned since the inception of this, and other threads on the issue of mediums! I can't thank Al enough for his tireless intervention and contributions, helping me, and scores of other growers to gain the most out of our gardening hobbies!

    I'm now ready to amend what I originally wrote, some of which I wouldn't say today. For example, I no longer recommend cocopeat or coco coir products, especially if other medium ingredients are available. Experience has taught me that they're more trouble than they're worth, and that peat is not the finite product that certain sources and industries would have us believe.

    Al's articles and written discussions have gone a long way toward putting all the pieces of the growing puzzle together for me, and as a result of applying what I've learned, I'm a much better gardener!

    I can hardly believe it's been so long since I first went in search of a better way to grow! This discussion was begun in 2008, and here it is, 2011... my, how time flies when you hold such knowledge and success within your grasp! :-)

  • thesss
    9 years ago
    last modified: 5 years ago

    Thanks Al! Appreciate the help in advance. I know I'll definitely need some :)

    Jodik, I'm glad you posted about Coco Coir products. The feedback on these have somewhat been 50/50. I'll stay away from them :).

  • jodik_gw
    9 years ago
    last modified: 5 years ago

    In my experience, cocopeat holds way too much moisture for too long a time to be of benefit in a potting mix. I also found that it grew some incredibly colorful molds, such that I've never seen before. Just those two items turned me off to using it. But wait! There's more!

    Due to processing methods, coco coir products contain an enormous amount of saline, which needs to be thoroughly rinsed and/or soaked from the product before using. Even the product that claimed to be pre-rinsed required an overnight soak and more rinsing before the water ran clear.

    How can a product have a small energy use footprint when it must be processed, and then shipped halfway around the planet to be used by growers? It can't, so it's not as "green" a product as we're led to believe. Peat is harvested in Canada, so its travel to reach us is relatively short.

    If all that isn't enough to make a grower think twice about using it, the rate of compaction for cocopeat is incredibly fast! I used it to pot up some bulbs several years ago, and within the space of a few months, the level went from full pot to about half a pot of product. I was not impressed. Upon un-potting those bulbs, I found dead and rotting roots, discolored coir from over-saturation, and the roots that were still live were growing upward toward a source of oxygen.

    I simply can't recommend a product with so many negative points.

    My experiences were my own fault, though... I neglected to research, and instead took the word of someone without asking why or how it worked. Lesson learned.

  • esoltan
    9 years ago
    last modified: 5 years ago

    Hey everyone,

    I had a question about substitutes for the gritty mix ingredients. I am able to get my hands on Repti Bark for the bark fines. I ordered Manna Pro Poultry Grit as the substitute for Gran-i-grit. I've seen in some posts where people used perlite, or that Napa dry oil stuff instead of Turface. Are these good replacements? I searched for Turface through the manufacturers website and there doesn't seem to be a local business that carries it. I know the importance of Turface as the media that will hold most of the moisture content in the soil, so I don't want to replace it with a sub-par media.

    Also if anyone has had good results with any other substitutes for the other ingredients, that would be helpful in the future.

  • tapla
    Original Author
    9 years ago
    last modified: 5 years ago

    The calcined DE is an appropriate substitute for Turface MVP/Allsport if you can't find it, and the perlite can be substituted for crushed granite in a pinch, but both substituting either would probably change the ratio of the ingredients slightly. When you decide on what you're going to use, let me know, and I'll suggest a mixing ratio that will approximate the water retention of the basic mix.

    What city do you live in - I'll see if there is a nearby source for Turface.

    Al

  • esoltan
    9 years ago
    last modified: 5 years ago

    Thanks for the help Al. I live in NYC. I was thinking about making a small batch with left over materials that I have so I can get rid of some clutter before I make a larger batch later with the repti-bark, poultry grit, and turface (or substitute).

    I have some orchid bark mix that I will probably have to snap into smaller pieces. That orchid mix also has a small amount of carbon chips mixed in as well. And I also have some perlite that I screened to remove the dust and small particles, but will probably have to screen it again with another screen size to remove more of those smaller pieces.

    Oh by the way, What your opinion on the use of repti bark?

  • tapla
    Original Author
    9 years ago
    last modified: 5 years ago

    It's fine, but particle size is important. From what I've read, it comes in 2 different sizes & the smaller size is more appropriate. 1/8 - 1/4" is ideal. See Gary's picture upthread dated Aug 30, 08 - it's perfect.

    Al

  • esoltan
    9 years ago
    last modified: 5 years ago

    Sounds good. I will definitely check my local pet store and see if the size is what is need for this mix.

    I went back and read a good amount of the original Soil Discussion and saw that you helped someone from the NYC area in the past. Do you know of sourses for all of the ingredients for the gritty mix around the NYC area?

  • tapla
    Original Author
    3 years ago


    Here's the original discussion (click me).

    ..... I want to change all of them to the TGB [gritty] mix. I'm
    afraid that my plants are going to get shocked with the change. Is
    there a proper way to do it?
    The best way to do it is wait until the summer solstice; bare root; do repot, keeping in mind where the roots are located in the new soil mass, and make sure you keep the soil moist where the roots are. Sometimes it's a good Idea to lightly cover the top of the soil with a piece of plastic wrap or other barrier that slows evaporative water loss from the soil until roots start colonizing the pot's deeper reaches.Make sure you keep your plants roots WET the entire time you're working to bare root them, too.

    Secondly I have a little indoor herb garden would the TGB mix work for that too? Yes - no reason it shouldn't. It won't make the herbs like indoor conditions any better, but it should alleviate limitations that can occur from over-watering/soggy soils ..... something most herbs tolerate poorly.

    Santolina (aka lavender cotton), an herb, in the gritty mix.

    Al

  • litterbuggy (z7b, Utah)
    3 years ago
    last modified: 3 years ago

    Yoly, your mind will really spin when you start reading the endless threads about container soils, water movement, fertilizing, and everything else Al and others have so generously shared with all of us. In my case, it took a little while for the point of all this fuss over growing media to 'click.'

    Most of my plants are still in MG, but with better watering (with diluted fertilizer every time), better draining practices, and improved light, most have started new growth which also helps dry the soil up faster than it did when they were just barely hanging on.

    In case Al doesn't recommend repotting your plants now, here are some brilliant posts by Al and deeper discussions that might help. Heck, I've even gone back and read some of the earlier 21 Container Soils threads...but I'm a real geek, so there's that.

    Lenore

    Dealing With Water Retentive Soils

    Container Soils-Water Movement and Retention XXII

    tapla thanked litterbuggy (z7b, Utah)
  • willzbernard
    3 years ago

    Al, I have one of my citron seedlings in your gritty mix and its about a year old now and doing well thanks to you. I know you recommend yearly trimming of roots as you write in your post called "trees in containers". I would like to trim the roots and replace the mix when necessary, but you've written that gritty mix lasts a long time and now its not even a year old (I switched it to gritty mix from regular soil about half a year ago). So am I supposed to bare root it and trim the larger roots and then replant it in the same gritty mix that I just took it out of, or do you have a different way of trimming the roots when there is no need to replace the soil? Also, after how many years would you recommend replacing the gritty mix?

  • tapla
    Original Author
    3 years ago

    Most of my plants get repotted every other or every 3rd year. Only a very few get repotted annually, and those are the plants with extremely vigorous root systems - hibiscus, datura, brugmansia, ........ These aggressive root-growers are almost always potted in the 5:1:1 mix.

    I don't reuse any part of the gritty mix, but a lot of folks do. Most often they allow it to dry completely, then pour the dry soil into a tub/wheel barrow filled with water and just skim off the organic fraction as soon as it floats to the top, and collect/reuse the mineral fraction.

    Nothing is carved in stone insofar as how often you should repot. The information that plants start to decline about the point in time where the root/soil mass can be lifted from the pot intact is a bit of information that's meant to be helpful, not something by which you'll be judged. I have so many plants growing on as potential bonsai that I often feel overwhelmed by the number of plants that could stand to be repotted. So, I weigh how badly the plant might be root bound and make my decision based on how much vitality/development/growth I'd have to sacrifice if I put repotting off until the next appropriate time rolls around a year later. For the most part, I'm usually ready to sacrifice some of the plants potential for a years reprieve from repotting it. Another way of looking at it is, if it's a case where I consider the plant on the borderline of being in need of repotting, I'll let it go another year every time. If I know the plant's really going to take a hit if it doesn't get repotted - I repot.

    Keep in mind though, that because I clearly recognize the benefit of regular repotting, my standards are quite a bit higher than those of the grower who buys a plant in a pot its life will end in w/o ever having been lifted from the pot. A serious hit to me is a matter of course to a very high % of growers who have no concept of the limiting effects of avoiding root-related work or even potting up. That's not a scolding, just an illustration of how different 2 perspectives of the same plant can be.

    Al

  • willzbernard
    3 years ago

    Thanks Al. I guess I'll hold off on repotting that one for another year or two, even though I wanted to cut the tap root to make the roots grow flatter. I have my citron trees in a grow tent for a few weeks now, under a LED light, and they are growing like crazy. I guess they really like the conditions, around 79 degrees F by day with 50% humidity, and around 68 F by night with about 62% humidity. I have a few of them in regular soil that I would like to get into gritty mix. My guess is that I should be able to repot anytime through the winter as long as they seem to be growing well in these conditions. Is that right?

    Also, for the future once they start fruiting (a while still) I would like to avoid a total bare root for religious reasons (need to wait three years to use fruit after a total bare root). I was thinking of using the wedge method you describe for evergreens, replacing a third of the soil every year. Can you think of any way of planting them that would make the root pruning easier without a total bare root? I am thinking of using the smart pots (I know you like the air pots better, but they are way more expensive) so I would have a healthier root system to start off with,

  • tapla
    Original Author
    3 years ago

    Your growing experience is about what you want it to be. I don't want to make up your mind; I'm much more interested in providing the information that allows you to make your own informed decisions and avoid disappointing results. I'll argue what's right or wrong in terms of facts and concepts or weigh in on what I think would serve the plant best, but in the end, it's your growing experience, not mine. I agree that you should be able to repot anytime during the winter as long as the conditions you are reporting aren't going to change.

    The primary factor that determines whether or not I use the wedge method of repotting is how the roots grow. Roots that branch like the top of the tree aren't likely candidates, while roots that grow dense mats of fine roots are. Your tree is the former, but that doesn't mean the wedge method won't work. It wouldn't work well for bonsai applications, but there's no reason it can't/won't work for conventional container culture applications. I can't think of any way of planting them that would make the root pruning easier without a total bare rooting, but once the plants are in the gritty mix any existing root issues have been corrected, subsequent repots are both easier and less stressful for the plant.

    Al


  • Yoly Garcia
    3 years ago

    Thanks AL and Lenore, I'll wait eagerly for June, I would love to see my plants being as healthy as they can be, so I'm sold. At least I'll have more time to look for the grit and the right pine bark fines, sadly it's been quite an ordeal finding them. Apparently in south Louisiana they use Oyster shell instead of grit so the only chicken grit I found was a bag of 5 pounds for 8 bucks! and I have called every landscape store I found in Google and went to every big box store I could find but no luck. Maybe I'll have to plan my next vacation to a place where I can get the grit and the bark hehe. Anyway I'm determined.

    Thanks for such valuable information, it's been quite an eye opener. I'm so glad to have found y'all.

  • litterbuggy (z7b, Utah)
    3 years ago

    Just one more suggestion--I've heard that John Deere stores carry things like turface and grit...but it probably depends on the location. Also, Al has said that fir and hemlock bark are perfectly good alternatives to pine bark.

  • willzbernard
    3 years ago

    Midlandhardware.com has cherrystone size #2 that is basically the same as grit and it is the right size. The price is about $5 for 50 pounds plus around $10 for shipping.

  • Yoly Garcia
    3 years ago

    Sadly they closed the John Deere store on Baton Rouge, but thanks for the other two alternatives for the pine bark, I'm sure that is gonna make my search a lot easier. $15 total for the grit doesn't sound bad at all considering we paid 16.50 for two 5 pound bags. Thank you for taking the trouble to help me. I don't know what I would do without it , God bless.

  • jadelab
    3 years ago

    Hi Al and everyone, I have been following these two discussion threads avidly (and taking notes as I'm brand new to collecting and tending houseplants). What a revolutionary (to my mind, at least) new way to actually understand what's going on for a plant and what kind of soil they need!

    Al, I've got a question after doing my best to digest all this information. I've read through so many responses where you and others mentioned adding things like gypsum and lime to soils or Epsom salts to fertilizing water. But I don't know enough to know when I would need to add this to soil for a houseplant. My questions is, if I am making the 1:1:1 gritty mix for my houseplants, do I need to add lime, or gypsum, or something else to that mix? I was going to just make the mix and water with a diluted Foliage Pro 9-3-6. Is this sufficient? I have a couple of beautiful, rare little plants being shipped to me next week and I really want to start out on the right foot (root? leaf?) with them.

    Many thanks to you and everyone who's contributed for such a fascinating discussion!

  • tapla
    Original Author
    3 years ago

    Thanks for the kind words, J! ..... and HI!

    You said: I've read through so many responses where you and others
    mentioned adding things like gypsum and lime to soils or Epsom salts to
    fertilizing water. But I don't know enough to know when I would need to
    add this to soil for a houseplant. My questions is, if I am making the
    1:1:1 gritty mix for my houseplants, do I need to add lime, or gypsum,
    or something else to that mix? I was going to just make the mix and
    water with a diluted Foliage Pro 9-3-6. Is this sufficient? I have a
    couple of beautiful, rare little plants being shipped to me next week
    and I really want to start out on the right foot (root? leaf?) with
    them.
    Most hobby growers get stuck on the idea that nutrient A is for one thing, so if you want more of that one thing, add more A. That's wrong in more than one sense. A plant needs ALL the essential nutrients for normal growth of ANY organ, and adding more of something when the supply is already adequate has only the potential to be limiting. An excess can't be a plus.

    That said, how you can effectively supply Ca and Mg is tricky if you're not using a fertilizer that already has them. Foliage-Pro 9-3-6 already has them, and it's all you need as a nutrient source to grow healthy plants. The pH of the gritty mix gets too high if you use dolomite (garden lime) as a source for Ca and Mg. So, if you're not using a fertilizer that has those nutrients, you need to supply it. The 5:1:1 has a low starting pH, so using lime to lower the pH while supplying Ca and Mg kills 3 birds with one stone. Since you shouldn't use lime in the gritty mix, you need to have a way to supply Ca/Mg w/o raising the pH. Since CaSO4 (gypsum) and MgSO4 (Epsom salts) are essentially pH neutral, they serve as a good source of primarily Ca and Mg, but S too.

    All you really need to know to be sure you're on track, nutritionally, is that 9-3-6 is all you need if you're using it.Let me know if this leaves you with other ?s.

    Al

  • jadelab
    3 years ago

    Al, thanks so much for your prompt reply! This clarifies the role of various soil additives in supplying the full range of nutrients a plant needs. I'm looking forward to trying out the gritty mix and fertilizer combo and watch my plants thrive.

  • willzbernard
    3 years ago

    Hi Al. I took your advice and root pruned my citron seedling and then set it in the gritty mix. For some reason it actually took around three months until I started seeing new growth again. Now I am getting severe chlorosis on almost all the leaves. Here is a little backround info; I water every 2-3 days with foliage pro with a 1/4 teaspoon per gallon. I thought it was the Ph of the water which tested at about 7 so I have been adding a little vinegar to bring it down to 6 but that hasn't done anything. Also, the light is on around 12 hours a day.

    When I reppoted I used 1.5 times the amount of turface more than the other 2 ingredients as I was using a fabric pot which dries out faster. The temperature in my grow tent pretty much stays around 75 degrees by day and 65 degrees by night with about 50% humidity. I would think its not getting enough nutrients but I don't think adding more fp is the answer, the question is whats preventing the nutrient uptake.


    Also, I know now is the time for me to move it outside as I live in N.J., however I am hesitant because it requires much more care outside, because I need to constantly spray for pests, and I need to always be aware how much it rained and how hot ect. and to adjust the fp based on how often I water. How important is it to move it outside for spring and summer?

    Here is a pic of the tree.

    Close up of the same tree



    Also, the tree next to it is in gritty mix for over a year but needs to be repoted because the particles are too big (my first try), and the pot is already too small, thats why I need to leave it in a pan that holds the water until I finish sifting everything and get it repotted. That one also has severe schlorosis. Here is a picture.

    And then I have another two citron trees to the right that are in dirt for now and don't have any schlorosis but have a different issue with curved leaves. I thought maybe too much fp and was giving them plain water for a while but it didn't change much. I know I can always count on your advice Al as almost anything I know comes from you, and thanks in advance!

    Here is pic of curved leaves trees


    And a close up shot

  • tapla
    Original Author
    3 years ago

    Can't be sure, based on what you said, but something is amiss. Ca and B deficiencies are noted for producing the symptoms shown in your images. B deficiencies are rare, Ca deficiencies not so much and can be a cultural issue as opposed to a deficiency caused by an inadequate supply of Ca in the soil. When Ca is present in appropriate amounts, soil saturation often inhibits uptake. Low light (and the plants are not getting enough), cool temps, and other cultural influences that slow transpiration all contribute to reducing transpiration, which slows the nutrient stream and limits Ca supply to forming leaves. Ca is immobile in the plant, so it must be present in the nutrient stream at all times. Are you actually checking your soil for moisture content before you water? Did you screen the Turface, and did you use MVP or Allsport and not a finer grade? My sense is that watering the plant in the image, indoors, every 2-3 days with a mix heavy on Turface is probably way too much water. I have trees under lights (which increases water uptake) with twice the mass and in half the soil (the basic gritty recipe) that I water every 5-7 days.

    The other thing that strikes me is, it also looks as though there could be a toxicity issue. Can you think of anything that might have made it's way into the soil that is potentially phytotoxic? What did you use for bark? grit?

    Al

  • willzbernard
    3 years ago

    Thanks for your response Al. I haven't been using a water meter, but I feel the bottom of the cloth from the outside and its dry, which just means there isn't a ton of water sitting there. I'll try the meter, but I just hate sticking in the stick because I feel like its potentially breaking roots. I used pine bark from agway that I screened and the MVP turface that I screened and I used #2 cherry stone for grit that I also screened. Also, it can't really be from the ingredients because the with the second plant with the same symptoms I got all 3 ingredients from different bags, and that one has regular chicken grit. If it is due to a lack of light why would only the ones in the gritty mix be suffering. I guess I'll try buying another light, but for now I think I'll put them outside and see if it helps. Any idea what the curled leaves on the other 2 plants are from?

  • willzbernard
    3 years ago

    I just picked up the plant to move it and I see that the two wooden slats it was resting on (to allow drainage to the pan underneath) are a little black on top from mold coming in contact with air. I guess the water dripping through the cloth was wetting the wood was growing some mold underneath the pot. Can that be the toxicity issue, even though the second plant which is not on wood has the same symptoms as well?

  • litterbuggy (z7b, Utah)
    3 years ago

    Willz, I'll let Al answer your more nuanced questions, but it occurs to me that you absolutely have to check the middle of the air pot for soil moisture, because the bottom surface of an air pot would be about as dry as the soil surface of a 'normal' pot.

    A moisture meter is actually less reliable than a dowel because it measures conductivity, which means that minerals can throw it off. And I (and hundreds of other much more experienced growers) have been pushing dowels through rootbound and freshly rooted plants willy-nilly for ages with no ill effects. Simply put, the number of roots affected by a thin dowel are nothing compared with the importance of having a reliable, accurate, and no-brainer way to monitor soil moisture.


  • willzbernard
    3 years ago

    OK litterbuggy, I'll try using a dowel from now on. I just moved them outside and I'll see if they recover. I suspect that it was the mold growing on the wood that was phytotoxic, when I picked up the wooden slats there were a bunch of tiny bugs crawling on the bottom that I would guess were booklice feeding off the mold. I guess I'll need to figure out a different way to elevate the heavy pot next winter.

  • willzbernard
    3 years ago

    Litterbuggy, maybe you can give me some advice on how to use a dowel. I tried sticking a thin wooden skewer (like a foot long toothpick) into the gritty mix just a few hours after I watered and it seems to come out dry even though the surface is still moist. My water meter also shows very little moisture readings when I stick it into the gritty mix even though I just watered? What am I missing?

  • rina_Ontario,Canada 5a
    3 years ago
    last modified: 3 years ago

    I am sure litterbuggy will answer, here is what I do: I use gritty mix (made of only grit, perlite and some turface) and use bamboo skewer if unsure. I leave it in the mix for just few minutes, but stick it deep inside. When you take it out, touch top of your hand or your cheek to feel if it is damp. It feels cold when damp/wet. If mix is quite wet, there could be small particles sticking to it too.

  • litterbuggy (z7b, Utah)
    3 years ago

    I haven't potted anything into gritty yet, but I've seen posts saying it takes a while to get used to watering it because the water drains so fast. Al has said he waters pots of gritty mix twice in one watering season, with maybe (I think) 15 minutes between watering, to give the turface and bark a chance to take in the moisture. Leaving the tell in the mix for a few minutes should help get an idea of the moisture, but keep an eye on the plant too.

  • willzbernard
    3 years ago

    Ok. Thank you both for the advice, I'll try it and see how it goes.

  • Al Farley
    2 years ago

    Tapla, while doing some searching for turface i ran across this, and was wondering for planting purposes is this an acceptable replacment fo turface.... : As most of us clay users know, calcined clay sourced from Montmorillonite is the preferred choice...but difficult/pricey to obtain. The next best alternative to Montmorillonite is Bentonite, which happens to be more available and real affordable--if you know where to look.

    For the past several years, my source for calcined Bentonite clay was an oil absorbent (Oil-Dri) sold at Wal-Mart for less than $5 for 25 pounds. Well, this past week I discovered that Wal-Mart will not be carrying Oil-Dri anymore....and I don't need a pallet of Turface or ProChoice (minimum order $500) so I researched a new source for calcined clay...and found one, at Walmart (lol).

    In addition to oil absorbent, Oil-Dri also packages calcined clay for kitty litter (100% calcined Bentonite clay) sold under the brands: Johnny Cat, Cat's Pride and Walmart's private label "Special Kitty".

    I bought a bag of Walmart Special Kitty Natural Cat Litter https://www.walmart.com/ip/Special-Ki...-Cats/10293705 for $3.87 (cheaper than Oil-Dri) and compared the clay with Oil-Dri; it is identical and confirmed with Oil-Dri (owned by EP Minerals) that the kitty litter is 100% calcined Bentonite clay.