Crushed limestone as a soil component can cause pH to get so high it makes many nutrients unavailable for plant uptake. Plants (including carica) only use about 1/10 as much Ca and Mg as N. Dolomitic lime supplies Ca and Mg in an approximate 4:1 ratio Ca:Mg. When this ratio gets too far off the 4:1 mark, the element that is high in the ratio creates an antagonism and affects the uptake of the other. With limestone, you have no idea how much Ca is present in relation to Mg.

I use Turface and crushed granite in the mix to allow me to fine tune the water holding ability of the soil. If you increase the volume of Turface and decrease the volume of granite, the soil holds more water. If you decrease the Turface and increase the granite - it holds less.

I pay about $5.50 for 50 lbs of 'Grani-Grit' brand crushed granite, which is a little more than half of what Turface costs. Since Turface costs more at about $10/50 lbs, but is about twice the volume, it costs about the same per cu ft.

Nothing is carved in stone here (no pun intended). ;o) Use perlite if you prefer, in place of the granite. I like the extra weight because it adds stability to the containers & helps keep them from marching off the grow benches.

Take care.

Al

Thanks for the reply, Al. I see now that using crushed limestone in place of granite would be unwise, and I see that I need to buy the dolomitic lime while it is available. Never seen it here before.

Now to specifics:
What advantage would be lost to potted fig trees if one were to substitute fine graded pea gravel of the same size for the granite? The poultry grit is around fifteen cents per pound, and filling 25 gallon pots would soon be costly.

Second question: What would be the result if one were to use the crushed granite I described, the largest pieces marble-sized, grading on down to about an eighth of an inch? Does the decreased surface area affect aeration?

LOL, I've made up my cheap Bohemian mind to spring for rhe poultry grit if need be, but I'd still like your opinion on those two items.
Ox

Drainage and aeration are affected by a combination of particulate size and particulate uniformity. As an example, it's easy to imagine that a quart jug filled with BBs will drain very quickly and hold lots of air, but if you add a pint of play sand (it will fit - I've tried it) you have 3 pints in a 2 pint container - right? ;o) What does the sand do to aeration and drainage? It slows drainage & decreases aeration. Conversely - if you add perlite to pudding, will it drain any better?

Like I said upthread - nothing is carved in stone. I have found that nothing I've ever yet tried suits my trees better than the equal parts recipe I shared, but if you can't find granite at reasonable prices, you'll need to make something else work.

If your soils have too many large particles they will drain to quickly. If they have too many small particles, they drain too slowly. The trick is to get as many of the soil particles in that 1/16-3/32 range as possible. Why not try going to a pool supply center or a masonry supply store & get the coarsest (silica) sand they have? It will even be pre-screened. Just be sure the particle size is 1/16 inch +.

Al

Thanks, Al:
I'm good to go now. I went back and read your posts concerning the mix using too-large particles.

The screened pea gravel I saw where they had the crushed granite was just the size needed, no larger than the poultry grower grit I feed my chickens. It should be just the same size, or a tiny bit larger than, the aggregate particles. I'll look again; if it is not suitable I will just grit my teeth, close my eyes and buy a few more sacks of granite.

I really appreciate your help here. Judging from the posts I read you must have the patience of Job. Thanks again.
Ox

I really hate to be the guy that gives a totally different perspective but here is my two cents about what to include in a potted mix for figs. First of all I think its important to not spend an arm and a leg for results when you don't have to.
I love your enthusiasm Tapla but Honestly I would never use any sort of bark in my potting soil mix. Mainly because through various microbiological processes it "locks up" nitrogen in the soil which generally is the single most important nutrient for plants. Your mix is wonderful for drainage but you want to find a happy medium of retaining moisture and draining it.
For the mix I would use a combination of compost mix of various sizes to help retain moisture and drain it. Another perk is that you can make compost at home for free! I am also a huge fan of Turkey manure so I would use some if that as well. For anyone that has used it knows how great this stuff can be for plants. If you want you can use a mixture if greensand and some organic slow release fertilizer to provide you with a complete nutritional profile you can but it is not "necessary". If you provide the plant with soils heavy in organic matter (i.e. compost, manure, peat) microorganisms will break down that matter and release it to plants through out the growing season. Other than that you wont need to add much more than a few inches of free compost every season.

Being stupid me!

All I care is for the right medium to make THEM figs
rOOt without roTTing!

Once established, they will NOT give a d*mn about
anything else, apart from not being in a deep swamp/desert!
Anything else will just do fine. Some kind of a mild
manure/fertilizer should make them happier...

George (NJ).

Also, remembering their origin;
figs DO love the warm sun bright light.

Tapla, Really enjoying this thread.
Would you comment on coir vs pine bark?
Your suggested ingredients are relatively heavy, how do you mix them? What is your largest pot used for figs, and how often do you repot (rootprune?/upsize?) with this mix?

Fignut,

I use the following as a guide (all are my guesstimates for dry/not so wet ingredients):
mulch=8lbs/cf
perlite=3lb/cf
turface=38lb/cf
poultry grit=40lb/cf

A mix of 1:1:1 mulch, turface, and grit is almost 29lb/cf. Replacing the grit with perlite brings you down to about 16lb/cf. I don't have a nursery container with me, but I seem to remember a 5g container being 9"D X 12"H. This equates to about 12.7lb and 7.2lbs respectively.

I have trees in containers ranging from 1g to 35g with most being 3.4g then 12g. I have found root pruning and potting up are more of a function of the tree's growth and not the growing mix. Some trees need to be root-pruned and/or potted up more frequently than others. LSU Purple is a very aggressive root producer... so much so, perhaps it doesn't belong in a container. Other trees of the same age (Rattlesnake Island, Black Ischia and Black Madeira as examples) had very modest root production.

The only reason I repotted all of my trees this year was to adjust the my growing mix to retain less water. I was able to reuse the mix I was growing the tree in last year and adjusted it by adding some Perlite and mulch. Some of the mulch had broken down, but not enough to motivate me to screen it.

My goal in using the mix along with the Air-Pots was to go three years between repotting. I think two years is going to be more realistic on the 3.4g containers and I'm still hoping to go three years between root-pruning on the larger ones.

~james

I'm getting old (OK, I am old - but fighting it) and looking for ways to do what I want to do without injury.
I really like the idea of the aeration achieved by this mix, but am worried about handling the weight while mixing or repotting. I'm only going to get older, LOL, and the longer these trees can stay in the pots, the better. I had heard that coir is very long lasting and had wondered if it might be used instead of pinebark. And while the perlite is lighter, it is also less durable. So am I going to need to repot before it breaks down anyway, making it more advantageous to go with the lighter material?
Last year I bought in different size airpots to get a feel for what size would be best for me. (Unless I manage to engineer heat traps, all my figs are destined for pot culture.) I like the "wrap around" feature - the pot can be stripped off the rootball with much less effort than is needed to pull it out. And hopefully the self-prune pot will allow longer periods between re-potting.
Am I right in assuming that warnings about avoiding overpotting plants wouldn't apply to this type of mix? Usually the plant has to be large enough to "dry out" the pot in a reasonable amount of time. But this mix holds so much air, that even water sensitive plants like figs might be OK in pots larger than usual for their size and not need repotting as often?
Thanks for all the information James.

I'm sorry I forgot to address how I mix it.

I use the Rubbermade 18 gallon totes. I have a two gallon white bucket (the local grocery store bakery gets donut filling in it) that I use to measure the raw materials. Two buckets of each ingredient will fit into the tote. I usually layer 1 bucket of material at a time. Then I transfer from one tote to another. About four transfers between the totes mixes everything together... especially if you can shake the supply tote while poring. This quantity is not too heavy unless your mulch is wet. If you still need to go lighter, you can use 1 bucket of each, and still make enough for about 1 1/2 of the 3 gallon Air-Pots.

I have three sizes of Air-Pots:
0.3g for rooting
3.4g for trees with ~1" or smaller caliper
15g for trees with ~2.5" or smaller caliper

I have a couple of trees in larger nursery pots. I have been toying with the idea of using 18"HX36"D Rootmaker container for the larger trees. They come in a long roll which can be cut to size.

I have not had a problem taking these steps. In fact, it was the Air-Pot distributor on Oregon who recommended it. As Al mentioned, none of this is absolute. There are trade-offs which can be made to meet your watering needs, weight requirements, etc.

Fignut: Coir is better considered a substitute for peat than pine bark. Coir & peat have a near identical water retention curve. They both hold just over 90% of their volume in water at saturation, and begin holding water so tightly it's unavailable to plants at about 30% saturation. Coir is easier to rewet when it drops below 30% saturation, which is the point where peat begins to become hydrophobic. Coir has a shorter fiber length than peat and compacts a little easier, also exhibiting a little less aeration. The pH of coir can also be a little problematic, coming in usually at around 7. If you're using coir in the soil instead of peat, you might be a little better off to use gypsum as a Ca source rather than dolomite & then supplement the Mg (your fertilizer may well be missing Mg) with the addition of Epsom salts each time you fertilize.

CHCs (coconut husk chips) would be an alternative to pine bark. The organic compounds that make up CHCs are primarily lignin and cellulose, so CHCs will not retain their as long as conifer bark particles of the same mass. CHCs should be leached thoroughly before using because they can very high in soluble salts. I have done 3 different comparisons between soils with the bark component replaced by CHCs, and in each case I found the soil with the bark component to outperform the soil with CHCs, even after thoroughly leaching the CHCs.

So, the salt issue, the high pH of CHC's (7), the reduced structural stability factor, the comparisons I've done, and because CHCs are substantially more expensive than bark, I chose to use pine or fir bark as the primary organic component of all my soils.

Re your overpotting question: As soil particulate size approaches 1/8", the level of perched water in the container approaches 0, so there is little or no saturated layer of soil to rot roots. You can grow very small plants in very large pots if there is no perched water table, or if the perched water table disappears very quickly. Conversely, you cannot grow small plants in large containers without sacrificing plant vitality when using soils high in compost or peat. Good root metabolism requires ample air in the rhizosphere that cannot be provided in/by saturated soils until roots have fully explored and colonized the entire soil mass.

Al

James - An afterthought: If you ever need/want to mix large - very large soil batches, simply dump all the ingredients onto a tarp. By pulling on the corners alternately & folding the mix over, you can have everything incorporated with nearly no effort in under a couple of minutes.

Al

LOL:
You guys crack me up. All that expensive Turface and crushed granite and you mix with a tarp! Get yourselves a little cement mixer!!!!

Throw the stuff in from one side, tip the mixer to the other side, dump it into a wheelbarrow or your pot and you are done.

Al, you could mix enough of your potting soil in an hour to make your garden club rich.

By the way, Al; I'm still exploring. Called a sand plant about ten miles from me today to ask about pea gravel. Lady said "You probably won't like our pea gravel, it is more like really big sand" "Well", I said, "What do you call it?" "Pea Gravel" she said, "but it is really, really little rocks". I may have found my aeration materiel.

Also, thanks for the discussion of "overpotting". My plan was to start all these figs in 25 gallon containers, half barrels. I would have been very disappointed to learn that this would be detrimental to the trees. Those "really, really little rocks" may be just the ticket to a well aerated mix.
Ox

I just mix shredded bark mulch (that has sat around for a year or so) with composted manure/compost and perlite. I also pack the bottom 1 1/2 - 2 inches of the pot with packing peanuts. Plant, top off with a couple inches of mulch and it seems to work well for me. Means I can move a ten-gallon pot and plant without needing moving equipment.

Maybe I'm being too lazy....seems that way (except for gorgi).

~Chills

Al
Ref perched water related; "you cannot grow small plants in large containers without sacrificing plant vitality when using soils high in compost or peat"
Perched water does become a problem for potted plants in Zone 5 during cooler months of the summer and more so with rains during these weeks.
Are there any techniques minimizing "perched water level" other than soil particulate size? It is said that a drainage channel is not a solution. Diminishing strength with age may prohibit use of high density rock particles as was mentioned in another post above. Any other suggestion?
Perlite is one possible solution but someone mentioned above about its short life. What is the "useful life" duraion for Perlite?

To remove perched water you can:

1) Use a pot-in-pot technique. This is accomplished by partially filling a container with soil and then nesting another container with the planting inside of it & filling in the perimeter space with soil. The perched water is 'fooled' into thinking the container is deeper & moves down into the soil in the lower container, leaving the top container totally free of saturated soil. In order for it to work fully, the depth of the soil below the top container must be equal to or deeper than the depth of the perched water column the soil will support.

2) Partially burying the container will have the same effect as the remedy above. The earth acts as a giant wick.

3) Push a wick into the soil and allow it to dangle below the container or just lie on the soil. It also 'fools' the water into 'thinking' the container is deeper than it is and the perched water drips off the end of the wick and/or is absorbed into the soil below.

4) After watering thoroughly, or during periods of heavy rain, tilt the container at a 45* angle (or close). Rather than the perched water occupying soil in the shape of a rectangle (in cross section), it will occupy soil in the shape of a triangle standing on an apex. This reduces the amount of soil that can hold water (the height of a perched water table is fixed by the soil structure and will be the same height in ALL containers) and so decreases the total volume of perched water in the soil. To confirm: Saturate any container holding heavy soil and wait for it to stop draining. Tilt the container and you'll see a substantial amount of additional perched water drain from the soil.

About your perlite question: I've never had any trouble with perlite failing structurally. I've grown in soils that have perlite repeatedly frozen in them for up to 3 growth cycles and have noticed no observable breakdown. I can't imagine that anyone would ever want to go more than three years in any soil w/o repotting and (hopefully) root pruning.

Al

Al et al,

If I haven't been completely bamboozled by all of the great cultural information here, I'm pretty sure that earlier in this thread you indirectly indicated that organic fertilizers will not perform well in your medium because the lack of biota necessary to break down those fertilizers and make them accessible to the figs. Am I correct or simply making things up?

I would like to remain organic in my fertilization scheme if at all possible, so I would appreciate any advice you may have in that direction.

Neil

I hope Ox is ok with us straying from the original topic - shout if you feel it's a hi-jack, Ox.

From above: "Organic nutrient supplementation programs in container culture are unreliable and erratic in their ability to deliver nutrients. The reason why is simple. 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 really can't help you much, Neil, and it's not just the media I use that I was referring to. I've just never been able to make good sense of the results of an organic nutrient approach in containers culture. I believe whole-heartedly in "feeding the soil and not the plant" in my gardens & beds, and though I respect the wishes of all who want to maintain an organic approach in container culture, I've decided to leave that approach in the garden for the reasons I've outlined.

Plants don't care where their nutrients come from, and I just don't care to deal with results I find to be unpredictable & often accumulative when cultural conditions for soil biota change from unfavorable to favorable. Maybe I'm a control freak, but I really feel like I have a much better influence over the vitality of my plants when the results of my nutritional supplementation efforts are swift and predictable.

Al

Al:
Hijack away. I'm like the kid at his first nudie bar; learning a lot here. Y'all just keep on keepin' on and I'll watch. I'd welcome your discussion of nutrition in mineral soils.
Ox

And here I've gone and left my pasties at home...

I seem to remember reading some literature on an organic fertilizer which has been processed so it does not require an organism to poop it out before it is useful to the tree. I do not remember the name of the fertilizer, but it was in liquid form. If you guys are so inclined to search about the hydroponic websites, someone may fnd it.

~james

Ox - for a lengthy discussion about fertilizers for containerized plants, click on the imbedded link. I strongly prefer a fertilizer with a 3:1:2 N:P:K ratio, like MG 12-4-8 liquid or MG 24-8-16 granular soluble for 95% of my plants, including the deciduous temperate trees.

James: Sounds like it could be some valuable info for the folks who prefer the organic approach. If you come across it in your travels again, would you forward it to me? I'd be very appreciative.

Al

In your search bar type in figtree.net and you will eventually get to the website of a nursery in Boston, MA which raises and sells Italian fig trees. Their formula for a growing medium is 3 parts potting mix (unspecified) and one part organic compost. They also outline a very specific plan for fertilizing figs growing in pots.

Thanks, Elder:
I notice that Figtrees.net in Boston lists their figs for zones 5 & 6.

Their pictures of trees ready to ship certainly are enticing.
Ox

Al,

Thanks for answering my question for what must be the 100th time. I appreciate your patience. Hopefully, James' memory and my (or others') search skills can locate this elusive organic liquid fertilizer that doesn't need microfauna to eat it before it's useful to our plants.

I understand your position on synthetic fertilizers for container culture and will simply have to bite that bullet if the organic fertilizer discussed above isn't available. Still, one holds dearly to one's ideals. Making a change like this is not easy for me.

Thanks for all of your valuable input on this and other threads.

Neil

Tapla, I was refering to the Coconut Husk Chips - I thought it was all called coir. I'd been told that it outlasted bark, but I don't doubt that you are right. So there is no point in even considering it.
The tarp "mixer" is brilliant - so simple, yet efficient, economical, and easy to store. It seems so obvious in hindsight, but I never would have thought of it, LOL.
James, If that Rootmaker product is the RootBuilder Expandable Container,# 30319, it looks as if it would be good for a plant that was staying put, I'd be concerned that it might not be rigid enough for trees that have to be moved for winter protection.
Overwintering brings up another question. How is this mix managed during dormancy? With my peat mix, I give the trees a good soaking just before storing, and that pretty much holds the pots until I take them out of the garage - no winter watering.

Fignut - My zone is a cold 6 & I overwinter all my trees (somewhere near 100) in the gritty mix I described upthread. I simply toss a few shovels of snow on them occasionally (2 or 3 times during the course of a winter) & let it gradually melt into the soil so they never go completely dry.

Al

Hi Tapla,
Wow you seem to know quite a bit about soil chemistry! I really enjoy learning more about these topics to broaden my understanding of them. Your comment:

"Even in soils where bark is the primary component, N immobilization is far less than in a peat based or compost based soil"
this one is really hard for me to accept when the the carbon to nitrogen ratios of typical finished composts are around 20:1 (and unfinished not much higher) and some barks having C to N ratios upwards of a 100:1.

There is no doubt in my mind that incorporating ground bark will increase humus content, CEC and structural components of the mix, but personally I would use them in moderation. These barks are not 100% Lignan and do still contain a portion of easily digested carbon.

"I never use compost in any container soil, simply because the particulate size is generally extremely small, allowing it to fill soil macro-pores....and if it is finished(the compost) it supplies no nutrients, so why use it?."

I would never use JUST compost in a mix, but personally from buying and making my own compost, particulate sizes of compost differ quite substantially. Using organic soils helps provide a great environment for a slew of micro organisms as well as the ever important earthworm (I cant imagine earthworms living in your mix.) Earthworms will create channels in the soil
and help with the whole aeration issue. In addition earthworms make earthworm castings which are rich in organic nitrogen for the plants. Compost actually does supply nutrients to plants just not directly. As compost breaks down further, and organisms like earthworms eat it and poop it, and other organisms eat them and maybe even their poop as well, massive amounts of nutrients are released in plant available form. However composts are not typically refered to as fertilizers.
Organic nutrient programs are harder to control. But if you attempt to keep all the elements (i.e moisture, temperature, ect.) within ranges, and provide good conditions for microorganisms then they will reward you.

You are right when you say that I have not tried your soil suggestion and it may provide a quite effective growing medium. However I personally value using easily accessible, natural,free, "waste" ingredients for my mixes, because of the not only the energy saved in the process but also the whole non-artificial aspect of it.

Kareem - As I read your posts I recognize another poster who wants to apply what he knows about gardening in the earth and composting to container culture. If you were talking about the garden, I would have little to disagree with, but since we're talking about containers, and the difference between gardening in the earth and container culture is stark, we differ. Container culture is far closer to hydroponics than it is to growing in the earth. I can see no advantage in 'feeding the soil' in containers in order to increase micro-organism and earth worm populations so they can quickly break the soil down into sludge.

You and I just have different perspectives on what makes a good soil - and that's fine with me. I have no wish to convert anyone to something they don't understand or they disagree with. However, in defense of what I set down and not as a boast, I can say that these forums are full of thank-yous and positive testimony that come from hundreds of people I have guided to a bark-based soil (or the soil noted above) because they were having major problems growing in a soil like you described.

Plants do not care what the soil is made of. I grow many plants in 100% Turface - sterile Turface - nothing else. You can grow perfectly healthy plants in a bucket of marbles if you wish. As long as a soil is not phytotoxic, provides anchorage, and holds the right ratio of air and water for the expected life of the planting, it will grow perfectly healthy plants.

I gave the OP a recipe for a soil that meets all these criteria and adds durability for the long haul as an added bonus, which he expressed a need for. ("I want my potting mix to last for several years." Undoubtedly, a compost-based soil cannot fill that requirement.) Container soils need not provide any nutrients - that's our job ... to provide all the necessary nutrients in the adequacy to luxury range and in the proper proportions. If we rely on a 'feed the soil instead of the plant' philosophy in container culture, I can guarantee that our plants will suffer diminished vitality.

Al

I just checked Ray Given's Page, and he recommends 2 parts pine bark, 1 part composted cow manure, and 1 part perlite. Mr. Givens raises figs in containers, and is a recognized expert in that field. For fertilizer he leans towards a slow-release type.

I don't remember if I've relayed this story before...so here goes (maybe again..)

I sat in on a tomato seminar in Houston a few years ago. Someone asked the presenter the perennial question, "What is the best tasting tomato?" The response was simply, "Any tomato which is perfectly ripe is going to taste better than any other variety which is not." Basically the thought is pick the ones that suit your needs/wants and maximize it. It doesn't matter how good the tomato is, if it can't handle the heat in Houston, its not of any use to me.

I think the same holds true for most things in life... including the growing medium we use to grow our trees in. There are many growing mixes that a fig tree will grow in (we've seen the pictures of trees growing out of the side of a wall). However, if someone in the desert was to grow their tree in the same mix using the same methods as a person on the Gulf Coast, their results are not going to be the same. In most cases, the growing medium you maximize will outperform those which you don't.

Pick a mix that meets your criteria. Mine was being able to water daily to reduce the temperature in the container and longevity of the growing mix. Yours may be water retention, or being light weight, or maybe you just like the smell of dung... find the growing mix that suits you, then tweak it until you maximize it. Ray's mix, Al's mix, even Walmart's mix are only a springboard. In three years you will be further ahead trying to maximize what you have rather than if you jumped ship every year because someone in Timbuktu's trees grew 4 more figs than yours did.

If the growing mix you have chosen just isn't going to work, or you want to try something new, you can always root 5, 10, 20 however many cuttings from one of your trees. Pot some in each of the different mixes (including your current one) to see how they perform against each other.

~james

This is interesting stuff you fellows are putting out. I suspect that each of the mixes mentioned will grow figs, but if one is willing to fertilize as required, the mineral mixes will certainly retain their structure for the long haul. On the other hand, if we repot every three years, most of the mixes mentioned will probably work reasonably well.

I have two questions: Al; are your plants wintered inside? Your comment about tossing on some snow made me wonder if perhaps they were outside, but outside they'd GET their snow without your help!

Second question; If we use the mineral mix, (bark, turface and granite grit), when we repot do we screen the material and use again, or do we discard all and start over?
Ox

Two to three years is the long-haul. If your tree is growing well, it will be ready to pot up within that time period. If you plan to keep it in the same sized container for an additional 2-3 years, it will need to be root-pruned.

Expanded shale, granite, Perlite, etc. are stable over a longer period of time than the bark. I had initially planned on screening the material, then replenishing the bark in the same volume that came through the screen. It became evident that unless the mix was dry, it would be difficult to screen out the smaller particles. They would stick to the larger ones.

Conceivably, one could have and extra batch of growing mix and rotate. The unused mix could be stored until dried, then screened and replenished just before the trees needed to be repotted.

~james

Just a note for those of you who are interested. I've been trying to learn how I could duplicate Al's growing medium without using granite.

Using crushed granite (poultry grit) in large quantities of potting mix is not practicable here. There are no local granite sources, so the grit must be bought in sacks at around $250 per ton. This translates to about $l5 or so for the grit in any one half-barrel.

In my search I learned that water filtration gravel of for municipal systems is almost exactly the size that Al specifies and is washed free of fines so that the municipal systems can use it. The gravel plant man I talked to called it "4 over 8". What this means, he explained, is that it passes thru a #4 screen (just less than a quarter inch) and is held back by the #8 screen (just less than 1/8th inch) In most areas of the country it should be easier to find than granite.

Dirt cheap, and the size matches the expanded clay (light weight aggregate) manufactured locally so that Al's mix can be duplicated. The granite will contain some micro nutrients that river gravel does not but, as Al has stated, we do not depend on this mix for plant nutrition.

Hope this helps some of the rest of you who may want to try the mix but are put off by the cost of granite & Turface.
Ox

everytime I read through these container mix posts I keep thinking that maybe Turface might make a better rooting medium (albeit a more pricey one) than perlite.

That being said, I am having more success this year in perlite mixed with potting soil than with just perlite alone.

~Chills

Chills,

Here is an experiment you might find interesting.

~james

Here is a link that might be useful: Soil substrate comparisons

Ok, I mixed equal parts of aged pine bark, Turface and perlite with a little lime. I mixed too, can I use the extra as potting soil for my Toms and peppers? If not, can I do so if modify it??
Thanks,

Secondly, I learned that Fafard sells pine bark based potting mixes per their website. A few varaitions but they all seem close to Al's basic soil with peat and perlite. My garden center had Fafard's straight aged pine bark.

The leftover soil should be ideal for peppers but will probably be a little fast (draining) for tomatoes. It will make very good houseplant soil, too.

Al

Thanks Al!!

So what should I add for the tomato mix? Pinebark or Turface or Peat?

Thank you

Wrong forum, Fred - but 5:2:1 pine bark fines:peat:perlite + dolomitic (garden) lime.

Al

Do these mixtures allow for fruit production?

New to site, need help to grow container figs from cuttings aquired from a 75 year old fig tree.

Thanks

In container culture, a good soil, with ample volumes of air and water/nutrient holding ability is the most basic, and an often neglected requirement for good tree vitality and growth of any kind - including fruiting. The rest of the puzzle comes together when provenance, the nutrition you supply, light levels, and temps are all favorable.

Al

Al -

Thanks for all the information here.

I am enjoying reading this thread.

I just wanted to ask your opinion of using typical growing mixes like MG in a clay pot vs. a plastic pot.

Since the clay pot is by nature more porous how well would that compensate for not using the soil mixture you describe? Would the compaction of the peat component still be a problem?

DO you feel that even in a clay pot the soil mix you describe performs better?

There are many variables to be considered in a discussion about soils. I'll tell you a little about 3 different soils & you can decide how different they are and if you think compaction/soil collapse will be a problem for you.

Peat based soils, like MG, break down quickly - within a single growing season. When you use them, you have to hope the container size and o/a plant mass is enough to compensate for the collapse toward the end of summer. Hopefully, the roots have colonized the container and the planting has matured to the degree that the plant is able to use the water from compacted soils quickly enough to avoid root rot. We hope that roots are healthy enough that they actually become a part of the structure of the soil and function as aids to the soils ability to hold air. For maximun vitality when using these soils, the plant should be bare-rooted every year.

Conifer bark-based soils break down at a rate around 1/4 that of peat soils. They virtually guarantee that the roots will become a part of the soil structure w/o much concern for root rot, as long as your irrigation practices are reasonable. The 5:1:1 mix of pine bark:peat:perlite is a good example of this type of soil, and there are hundreds of GW folks growing in it with very good results. You should expect at least 2 years service from this soil, as opposed to 1 from those based on peat. Your trees should have some attention paid to their roots every two years - 3 years maximum, so this is a good soil to use for your trees.

The third type of soil is the gritty mix described way upthread. It consists of equal parts by volume - pine or fir bark:Turface:crushed granite. It is 2/3 inert, so it breaks down very slowly and will still be very serviceable long past the time appropriate for you to do a repot/root-pruning. This soil retains its structure for a very long time, and could easily be pressed into 5 years service if the plant's becoming badly root bound before that wasn't a consideration.

Clay pots (or other containers that have gas-permeable walls) will always be healthier for your plants - no matter which soil you choose. The price you pay is the need to water more frequently, but that act of watering drives damaging CO2 from soils and brings in a fresh load of air - greatly beneficial to plants, both.

Can a clay pot help compensate for a collapsing soil?

Yes, to some degree it can. Roots begin to die only a few hours after being deprived of adequate aeration. The small and most important roots die first - then progressively larger roots until air again returns to the soil, allowing the plant to start a rejuvenation process. This cyclic death and regeneration of roots due to collapsed soil is very taxing from a stored energy perspective. The plant uses it's reserves or current photosynthate (food) production to regenerate roots. This means less increase in mass in other organs - including fruit. How the clay pot helps is by allowing air back into the root zone quicker, so not as many roots die when using a soil too water retentive.

Al

I am new o this and trying to figure this all out. I just visited my local home depot, lowes & 2 nurserys. I foung perlite, compost manure, mulch and a hot of potting soils by garden pro, scotts & miracle grow. But that was it as far a crcshed granite nothing and when I asked about the turface all I got was blank faces. I live on long island, NY. does anyone have any other ideas of how to either obtain this stuff or alter the mix?

Wow, I don't have anything like what this thread talked about for my figs growing medium.

I just planted my figs this week. I used garden dirt, some peat, some sand and organic fertilizer in the mix. Hope my figs do OK.

If I can make just one adjustment, would adding pea gravel help my mix?

Keepitlow, garden soil is not a good choice at all for a container plant. I would start over and repot if I was you. I think even a commercial potting mix would be better than what you are using, but something closer to Al's mix would be best.

Do you remember when your 5th grade teacher told the class "There are no stupid questions??" Getting ready to do some potting work on a really wild growing Colasanti fig and came across this thread. Thought someone else might want to review it also.

Thanks to all original participants of this thread - saved me some $$ and saved DH from back surgery :-))

DL

Do you remember when your 5th grade teacher told the class "There are no stupid questions??" Getting ready to do some potting work on a really wild growing Colasanti fig and came across this thread. Thought someone else might want to review it also.

Thanks to all original participants of this thread - saved me some $$ and saved DH from back surgery :-))

DL