poaky1

soil mix/recipe for a potted Agave baby

poaky1
June 28, 2019

I was wondering what soil mix to put together or buy for a new Agave Parryi plant. It is small now, should I start out with a small pot, or can I plant it in a big container that it will stay in for life? I will be leaving it in a greenhouse. I would rather just plant it where I would just keep it it's whole life IF that is okay to do. I've heard to NOT use peat moss in the mixture on some websites and others use peat moss in the recipe. I know to use a good bit of gritty mineral soil, maybe some lime, but what else?

Comments (22)

  • Stefan

    Just avoid vermicompost/humus (high acidity, high nutrition). Peat is ok, but i think agave would be the only plant id recommend using topsoil mixed with mineral components...

    Out of experience, they fare better in a clayish/less organic mix. As far as peat moss is concerned, its mostly a issue of volume and watering. Tends to compact because people mistakenly mix a lot more peat per volume than perlite or pumice or other stuff.

    Agaves (+ relatives ),as well as most aloes and crassulaceae have a fairly high tolerance for organic matter in their soil ...

    Now, vermicompost/humus is okay for cacti and euphorbia, if you use it in smaller amounts than you would peat. Its also preferable if you were to dilute it with coarse sand, or peat, it should work great, as long as its 20% or less of the soil volume. Avoid clayish for nearly all cacti( i think only glaucescens and other feocacti like it)....

  • PRO
    tapla

    Size matters when it comes to what potting media are comprised of. Large fractions of peat, coir, compost, topsoil, sand, composted forest products, in any combination ensure excess water retention. Particle size is the primary driver of water retention, followed by the internal porosity of the ingredients. Ideally, your soil will hold inside of porous particles, on the surface of soil particles, at at the interface where soil particles contact each other. This is possible only if all particles exceed .100" in size. A medium built as I just described would look something like this:

    How your soil is structured depends on what size container you can use. The smaller the particles and the larger the fraction of small particles (<.100") the more critical container size is. Particle size drives the ht of the perched water table. Perched water is water that resides near the bottom of the pot or perches above "drainage layers" and will not leave the pot because it's ability to stick to itself (cohesion) and to other soil particles (adhesion) is greater than the force of gravity. The ht of a PWT varies from soil to soil, but in any given soil, the max ht of a PWT is a constant, regardless of the size/shape of the container. If you are using a soil that supports 3" of soil and the container depth is 3" or less. After a thorough watering, 100% of the soil will be completely saturated. If the pot happens to be 12" deep, only 25% of the soil would be saturated, so tall pots are a better choice when your media support perched water.

    On the opposite end of the spectrum, container size is a nonissue when you use a medium like the one in the image above. If the medium doesn't support perched water, you can grow the tiniest seedling in a 100 gallon cattle trough if you're moved to do so; this, w/o your plant having to pay a vitality tax because you can't keep the root system happy because of the amount of water it retains.

    Al

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  • poaky1

    Okay, let me just give you guys more info. I have a VERY large container, possibly 5 gallon size, I should take pics maybe? It is a vinyl ( fake wooden barrel) that I've drilled many drainage holes in. I kinda need you to talk to me in "dummy" terms. I am NOT planning on using any compost or "forest products" in the mix unless you guys say to. I have that stuff, BUT, I also love growing ferns and shade plants that would love that stuff, I'd rather save it for those plants anyway. SO, maybe give ,me the dumbed down version of the stuff you said above. I have cheapo "potting soil" from Dollar General, Perlite, small bits of "gravely mix" that is meant to level stepping stones, and a little bit of Pea gravel. What should I add or subtract? Anything I should purchase? I mean in small amounts. Should I add some Lime (crushed to powder) I have that also. I DO have Peat moss already, MAYBE add a tiny bit? I am in Pa, so, I don't have access to any seashell pieces or anything like that.


    I will be buying a TINY Yucca Rostrata soon, and putting it in a GIANT pot, and leaving it year round in the greenhouse like the Agave, I guess THAT soil issue should be for a whole other post, though.


    Sorry to be needing the "dumbass" version of what you already said but, I kinda get it, big AND small particles for the soil, right?

  • rina_Ontario,Canada

    Not big and small particles...proper mix should be of relatively same sized particles. I do not have Agave parryi or Yucca rostrata, but grow quite a few succulents. They are potted in a mix of sifted perlite and chicken grit (about 1:1) and small amount of turface (maybe 10% of total). I do not use soil, but occasionally will add a bit if I am running short on ingredients and want to pot something immediately (again, maybe max. of 10% of total). I do have Agave ferdinandi regis and another one I do not have ID for (old photo, it is bigger now):


    They are both in the mix I mentioned, kept outside during warmer seasons and indoors in winter. Here is the photo of the grit and perlite - as you can see, they are of similar size:


    I have used aquarium gravel before, when I didn't have much chicken grit - some was green, visible in the 1st photo. In that case, it was used for topdressing.

    In the photo posted by Al (tapla), there is a small-sized bark in the mix. I do not use it because I can't get it where I live, otherwise I would. Cream colored particles in his photo is turface.

    I think pea gravel is too large for good mix, and am not sure what is "gravely mix" you mentioned.

    poaky1 thanked rina_Ontario,Canada
  • poaky1

    Hey guys, Thanks for replying to my post. I have written down your reply. OKAY, I understand what "sifted perlite" is, "chicken grit" is a bag of "pulverized granite" from what I have seen myself. I have a bucket of it. AS for "Turface" I don't know what it is. I will do a search what it is, BUT, NOW I am "clueless" about it. Aquarium gravel, I am sure a search (bag of gravel for an aquaruim) will tell me what that is, the 10% "soil" is just plain ole "dirt" EVEN IF I just dug into the soil in my yard, I could add 10% of THAT and it would be fine. As for the "small sized bark" I am NOT thinking ANY bark should be in a "soil mix" for an Agave OR ANY 'desert plant" even a Yucca Rostrata.

    I have read that SOME minerals or elements NEED to be added to a Agave's or ANY many desert plants soil. I will admit that I need to do much more research about it. I DO APPRECIATE your help BUT does ANYONE have a RECIPE for the best mix for an Agave Parryi? I mean breaking it down into parts? My "gravely mix" was just a bag of the stuff that is sold in bags at "Lowes" for leveling off" stepping stones. it is grey in color and just like "chips" of small grey gravel.

  • poaky1

    I do have a bit of orange "clay" soil. Can I add a small % of that, even if it is 10% of the total of the soil for the container? I want to since "clay" soil is rich in 'nutrients" or so I've heard. The rest can be "drainage rocks", ALSO "Is it okay to add lime to the mix? Meaning "pulverised lime", the stuff you can get at "Lowes" or HD. I ALSO have a bag of fertilizer for "palms and cactus's".


    Can anyone GUESS at a "recipe" for an "Agave Parryi" like breaking it into fractions, like so many parts this and that? IF NOT. I will try an search for it. ANYWAY, thanks to everyone.

  • Stefan

    Avoid clay, avoid lime. 30-35 % of volume topsoil or peat. 30 % of volume perlite. 20 % coarse sand. Rest should be large particles(leca, pumice, gravel, etc). Its a surefire mix, thats works even for moderately difficult plants....

    Id also advise, save gravel or lecca for top dressing(preferably larger chunks), or whatever small (large pebble sized) rocky material you can find.

    poaky1 thanked Stefan
  • poaky1

    I am wondering what else to add;. Maybe the stuff you mentioned is all that is needed?

  • Stefan

    I dont really add anything else. Im a full time container grower. What i described is the one i use... More organic material + bark is recommended for epiphyte cacti, and other non arid succulent plants.

    Maybe for some transitionals like echinopsis, but not much else...

  • rina_Ontario,Canada

    Pulverized sounds too fine to me - like dust. Maybe I do not understand the word properly...but anyting fine is not really suitable for making a well draining mix. That ncludes fine sand - note, Stefan suggested a coarse sand. It is sometimes sold as Horticultural sand. I posted photo of grit and perlite mixture, with measuring tape in metric and imperial, for you to see the size, Al posted photo of his mix too. There is no 'dust' or fine sand (like play sand) in it. Bark in small amounts is np, and I would use it rather than soil dug from the yard.

    Orange clay soil - did you buy it? Can you post photo of ingredients you have (not lime, but the orange clay soil and gravely mix to see their size)?

    Do not worry about ingredients you are not able to get easily - as you can see, there are many ways one can make a good mix. There is difference between ingredients used in mixes Al, Stefan or me suggested, and any of the mixes works well. Many ppl use just a 1:1 mix of Cactus & Succulent soil and perlite (or pumice).

    I buy chicken grit - not pulverized - in 50lb bags, for about $10-$12. It is granite chips (crushed granite), size 2 (or Grower size). Size 1 is too small, size 3 is too large. Here is photo of it:


    You may be able to find it under different name/manufacturer (Manna Pro is another common name), I am not sure what size bag you can get, but smaller it is - more $ it is...Aquarium gravel is used in aquariums/fish tanks. Do not go crazy looking for it - while easily available in any Aquarium/Aquatic store, BUT it gets more expensive, and I only suggested it as a substitute for chicken grit (it wouldn't be no 1 choice for me)...Same wih turface - available in 50lb bags for just under$20. But if you can't get it, do not worry abot it.

    Perlite is available in many stores (Lowe's, Home Depot, Wallmart, any garden center, hardware stores...) It should be sifted or rinsed to get rid of dust. Pumice could be used instead - whatever is available to you. I can't get it easily, so I don't use it.

    I am not sure why you want to use such huge container? It will require quite a bit of ingredients, and depending on what you'll use, it can get heavy.

    Sorry I can't offer you exact recipe, I offered you recipe for a mix I use for all my succulents (over 250 of them, including couple of agaves I have).

    poaky1 thanked rina_Ontario,Canada
  • PRO
    tapla

    FWIW - whenever you use ingredients disparate in size such that there is a large enough volume of fine ingredients to fill all the large air spaces between the larger particles, you do yourself a disservice because you would be going in the wrong direction as it relates to air porosity. To see this in the mind's eye, imagine a jar, the capacity of which is 50 cu. in.. It's filled to the top with any of the common ingredients you might use in a soil. For the sake of this point, we'll imagine a coarse ingredient like grower grit (crushed granite) or perlite and a fine ingredient like builder's sand or peat. Now, imagine you have a bag of marbles that each displace .5 cu. in.. Assume this mix remains homogeneous and mix the marbles into whatever you have in the jar and note what happens. The 10 marbles displace 5 cu. in. of material in the jar. Is the o/a air porosity of what's now in the jar go up or down? It decreased by 10% by adding the large particles. What happened to the air porosity of the ingredients that can support rot colonization - the smaller particles between the marbles? It stayed the same. So, you reduced the air porosity and the volume of soil available for root colonization, neither of which can be considered a step in the right direction.

    Now, let's add 10 more marbles, which results in a 20% reduction in o/a porosity and no change in the porosity of what's available for root colonization. 10 more marbles yields a 30% reduction in o/a porosity and STILL no change in the porosity of what's available for root colonization. Increase the total number of marbles in the jar to 80 and you're at an 80% reduction in o/a air porosity, ALL air spaces between the marbles is still filled with finer material, the air porosity of the ingredients between the marbles is the same as when we started, and there is only 20% of the original volume of medium to support root colonization.

    KEY POINT: When you start with a large fraction of fine ingredients and start adding coarse ingredients to "amend it to increase air porosity", it gets a lot worse before it starts to get better. Whenever you wish to take advantage of the added air porosity coarse ingredients CAN offer, it's essential that the coarse ingredients make up a very large fraction of the ingredients. 80-100% is what I mean by a very large fraction, and 80% is on the low side. So, even small amounts of fine material mixed into coarse material make very large differences in porosity and water retention. When it comes to porosity, the WORST soil one could grow in would be one that has a mix of fine/coarse material such that there is exactly enough fine material to fill all the spaces between the larger particles.

    You're MUCH better off to use a water-retentive medium just as it comes from the bag and eliminate perched water by use of ballast than to try to amend it to increase porosity by adding bark, perlite, Turface, grit, etc.. More than 95% of perched water can be passively eliminated by judicious use of ballast, which represents a giant step forward for growers who lack a good understanding of what drives water retention and how water behaves in container media. Still, eliminating perched water with physics tricks doesn't change the fact that soils that support enough perched water to cause you to act to reduce it are almost sure to have too little porosity. There is simply no substitute for well-aerated media that support little to no PW.

    Al

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  • poaky1

    Hello, I was going to use some clay soil from a pile that I had delivered years ago. I was going to use a small bit to add nutrients to the container that I was to plant the Agave in. IF I don't need to I won't. I was afraid that just a few potting ingredients that were insoluble would starve the Agave. I DO have a palm and cactus fert mix, though. It's granulated.

    As for the pot size, I saw that the Agave can get quite large over time, and wanted to save the trouble of messing with a large prickly plant. It is now tiny.

    I have a bucket of chicken grit already, granite chips, IOW. I have perlite, plus a bag of cactus and citrus potting medium that is small. It MAY have peat in it that I read elsewhere is NOT GOOD for desert plants, BUT, IF somebody here uses it and it's fine in small amounts, I'll add that.

    SO, all but the cactus and citrus mix will be the same size bits. IT MAY BE cactus and succulent mix, NOT citrus. I haven't got the bag out yet. I JUST got my greenhouse today, so, I haven't moved all my gardening things into it from the basement yet.

    IF a smaller container is best for now, I will use one first.

    So, IF I go with cactus and succulent mix, granite chips/pulverized, and perlite in a mix of 1 part each, is that likely to be good? I would add some fert for cactus and palms.

    Maybe Agaves and Yucca's don't need a lot of fert?


    The Rostrata would be potted in a giant pot since it gets so big. Thanks all.

  • Stefan

    Cacti and succulents do better when in adequate pots. It needs to fit the size. Planting in the soil is different. Too large=bad. Something about watering issues , roots drying out.

    If you cant handle agave spikes...well, dont grow cacti and succulents.

    Me? I had to replant a spiny to the brim 1,5 meter tall opuntia streptacantha.

    And it was WAY underpotted.

  • rina_Ontario,Canada

    Growing succulents in mostly (or entierly) insoluble medium doesn't starve them - you could fertilize (with some restrain :) if needed. Most grow naturally in very lean and gritty substrates, nobody goes around to fertilize them - maybe occasional bird or animal, haha.

    You could use any size pot you want, but overpotting is not really best. Too much soil for plant and if more water retaining, may take ages to dry up sufficiently. And it may not look the best - but that is JMO...Repotting into bigger pot give you chance to check out the roots too. It is not needed every year.

    You can make good mix from ingredients you have: grit and sifted perlite (in approx. same amouts), + smaller amount of C&S soil (or cactus & citrus). I would not add any peat, since there is likely some already in soils you have (read list of ingredients). I still wonder about your "pulverized" granite - already asked for a photo. Pulverized doesn't sound suitable to me.

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  • PRO
    tapla

    As soil choice moves toward media which support less & less perched water, the size of the pot becomes less & less important, until finally, when the PWT no longer exists, the grower could plant the tiniest of plants in a 150 gallon cattle trough w/o worry. The plants do need room for roots to run, though, if the grower is conscientiously trying to keep unnecessary stress to a minimum.

    Generally speaking, it's bad form to suggest we should try to replicate the soil and soil conditions that support plants in situ (not that anyone has). Reason 1 is, it might not even be the soil the plants prefer. It's very common for in situ plants to grow in a soil that barely allows them to survive; this, because more vigorous plants are able to out-compete them where the soil might be perfectly conducive to their well-being, but they're able to prevail over other plants on a soil, the dynamics of which might be considered mediocre to poor. Second, using soils that serve populations of plants (where they occur naturally) in a pot markedly changes physical soil dynamics, more often than not to the degree it won't support the plants w/o the grower resorting to heroic methods. The reason seedlings survive in earth's immensity is because the earth acts as a giant wick, removing water from between the soil particles. A pot does the reverse. It causes water to remain where no water would were the soil to be observed where it naturally occurs.

    My suggestion would be to concentrate on building a soil, the structure of which holds little to no water in excess (in air spaces between soil particles) and the structure of which prevails for whatever you believe the interval between repots (not potting up - that's different than a repot) will be. Your soil needn't provide ANYTHING in the way of nutrition; that would be your job, and it's monkey-easy in all cases where the grower is using a medium that allows watering to beyond the point of saturation, without worry the soil will punish the plant with long periods of soggy conditions. Flushing the soil when you water is important because it limits accumulations of salts from tapwater and fertilizer solutions, and it's like hitting the 'fertilizer reset button'. The average grower who is unaware of the fact that salts accumulate in soils, making water/nutrient uptake unnecessarily difficult (for plants) and causing badly skewed nutrient ratios in the soil. Antagonistic deficiencies, deficiencies where an excess of one nutrient causes the plant difficulty taking up one or more other nutrients, are pretty much the rule for growers who practice watering in small sips to avoid over-watering, which causes ALL salts from tapwater and fertilizers to remain in the soil. Over the long haul, this will kill even exceptionally vigorous plants.

    Al

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  • poaky1

    Hello, I bought bagged Cactus, Palm and citrus soil. The Miracle grow brand. I see on the bag that it has peat and "forest products" in it. I am guessing it has peat, wood fines and possibly coir in it. The "pulverized granite" is chicken grit. I would take pics but I am having trouble posting pics lately. I just tried to post 3 pics and only got 1 to post on the Tree forum. The grit is not powder, it's little chunks about 2 -3 millimeters wide approx. The gravely mix is about the same size but is grey.

    I will just fertilize a small amount. I have a shallow but wide planting bowl with drainage holes drilled in the bottom. It is plastic, It hasn't cracked over last winter with soil in it, so, I am guessing it should be fine if I reuse it and have my Agave in the greenhouse next winter in the bowl planter. I am trying to avoid repotting often by potting the small Agave in this wide but shallow bowl planter. It's about 6-7 inches deep and about a foot to 14 inches wide. I will use newspaper and gloves to pot it up. Once it gets a bit larger I'll try a bigger pot.

  • poaky1

    BTW, Stephan, I am kinda new to spiky plants so I don't know IF it would be hard to deal with the spikes. I had 2 that died on me from too much rain last winter. I NOW have a new greenhouse and am trying again, BUT will keep them out of the rain in the greenhouse.

  • Karen S. (7b, NYC)

    Forget the fertilizer, fresh soils don't need it, many succulents do fine w/ little to no fertilizer. You overestimate the plant's need for it.

    poaky1 thanked Karen S. (7b, NYC)
  • poaky1

    Okay, well, the bagged soil has fert in it, BUT, I was worried about over time. I will try and take some pics of the stuff I want to add to the bagged soil for Cactus, palm and citrus.

  • Stefan

    If youre kinda new , that i understand. But if youre not prepared to deal with the spikes, simply dont grow them. Now, i WAS afraid of needles and pointy things. Then i began growing cacti and succulents. Now....well, i do most things with bare hands, with the exception of a few that i use tongs for(really long and sharp spines, hard to hold, hooks, brittle spines, glochids). Nobody is pushing you to grow spiny plants. If you really want to, the spikes are an obstacle to overcome. It is something that needs getting used to.

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  • PRO
    tapla

    I think there's a general misconception that fresh soil contains enough nutrients to carry a planting for ___ months (fill in the blank) after establishing a planting w/o need for supplemental fertilizer. SunGro (the company that acquired Fafard) Black Gold boasts it contains fertilizer, but it contains only NPK % of .05-.00-.00, while Miracle-Gro Performance potting soil claims NPK %s of .19-.03-.03. These are minuscule amounts of fertilizer, only small fractions of 1%, and shouldn't be mistaken as a replacement for regular nutritional supplementation, even for plants that seem to prefer nutrients in very small doses.

    It's more the rule than the exception that growers view the "growth spurt" that occurs after repotting or potting up as proof the old soil was worn out and the new/fresh soil used provides a fresh shot of nutrients. This is a 2-part fallacy. First, what is considered a "growth spurt" is not a growth spurt at all. It's a visual cue the plant is now growing such that it's able to realize more of it's potential. A plant can NEVER grow at beyond it's genetic potential, so the growth/ vitality/ appearance of every plant is = to 100% of its genetic potential minus the effects of all limitations imposed by cultural conditions. So no growth spurt - just the plant growing at a bit closer to the potential it's had since it became a plant. The second part of this 2-part fallacy occurs when the grower attributes the growth spurt that isn't really a growth spurt to nutritional issues. In the sense the plant's pre-repot root conditions limited nutrient uptake, it is, but it's not because suddenly there was a higher concentration of nutrients in the soil after repotting/ potting up. Reducing the limitations of root congestion by giving roots room to run results in the immediate improvement in growth rate, appearance, and o/a vitality conspicuous after a repot and to a lesser degree after potting up (within the limitations imposed by other cultural factors). The improvement is not because the plant suddenly has a newfound reserve of nutrition, it's because the roots have an expanded volume of soil to colonize, and in doing so they produce thousands more of the fine roots that do the heavy lifting.

    Growers are best served by keeping their focus on soil structure and it's ability to retain that structure for the life of the planting. The ratio of air:water in soils is far more important to a container gardener because getting nutrition right when the soil is right is monkey easy. Nutrition is pretty much a guessing game when the grower is prevented from watering correctly (flushing the soil when watering) for fear all or part of the soil will remain soggy/saturated for extended periods, which limits root function and very often wrecks root health.

    Al

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  • poaky1

    Stephan, it was MY idea to grow Agaves (already have one in a 2 inch pot, needs to be potted up in a larger pot, thus my need to come here asking about soils to use to pot it up) I am NOT just asking about this to please anyone but me. I am not all scared of spikes, I am just wondering how to best handle them without getting spikes and barbs in my hands. I am pretty sure I won't die IF it does happen :) . I have that Agave Parryi already plus I have ordered another Agave, hardy to zone 5 but I am 6a. I also have ordered a "Cholla tree, a type of "pad" I'm guessing "Opuntia" type BUT with a sorta trunk to it, a Yucca Rostrata and a Quartz mountain Live oak. I already have a larger Quartz mountain Live oak growing in my yard, the ONLY live oak that will grow in my zone 6a yard, BUT, I will need to baby it until it gets some size to it, I'll need to baby it in my green house for winter for a long time. I will be asking a neighbor if I can have a pad from her "prickly pear" plant I had a big bunch of them, but, the area has gotten too shady and they got all mushy.


    Tapla, I don't know about the fert amounts in my bagged soil for Cactus, palms and citrus, BUT, as YOU said it doesn't matter too much with these plants, I THINK you meant that giving the plants enough root room means alot more than extra fert. My bag of that soil is in my greenhouse anyway, and it's dark out. So, I don't know the fert amount anyway. I am going to try a mixture of one part each of Perlite, chicken grit, cactus soil and another part of the small gravely grit that is grey and as small as the "chicken grit". OR I'll do the "chicken grit", perlite and the cactus soil each in one part each.

    I am kinda worried about the eventual size of the "Cholla tree", I may need to eventually plant it in a raised bed outside. It seems that it will get quite wide and tall. I have a raised bed I can put it in IF it can (good drainage) handle alot of rain. Meaning outside the greenhouse. I have a raised bed with 2 Yucca's in it already a Y. Recurvifolia and a Yucca I can't remember the name, it has regular foliage like a Baccata BUT it 's NOT a Baccata, it's supposed to get a trunk on it. Anyway, thanks for your input. If you have anything else to add as a tip to growing these plants speak up.

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