I for one agree with you for the most part. There are a lot of us growing rare fruits in containers...even some of our more climatically advantaged members grow some in containers. C'mon...say it again...."climatically advantaged". Y'all like that don't you? This is of course, quite the opposite of my climatically challenged area of Ohio. But I digress.

Due to my climate...I have no choice but to keep most of my plants container-bound. My plan all along has been to practice agressive pruning to keep the plants smaller and more manageable. The experience I've had with my apple trees is that the more I prune, the more apples I get the next season.

Is there a downside to this somewhere? I believe there is. Even if pruned well, these trees are going to reach some size. There's root restriction and then there's just a root mass where there is very little soil left in the container! We've all experienced that. You grab the plant by the trunk, pull, and the entire plant comes out of the container. Where the hell is all the soil? I can't see any benefit to the plant when it reaches this point. No way to retain moisture and other goodies that soil provides. Okay, time to root prune and replant. This is fine and dandy and I do this all the time...when the plants are manageable. This is not going to be the case when these plants reach a certain size/weight. This has been a huge concern of mine for some time. And I'm certainly open to any suggestions this group may have.

So while these plants that are grown in hard clay and other restrictive soils, they are still getting more benifits from that little bit of soil than I can probably provide my plants in containers if I let the roots take over the container. Maybe this is where the dissention stems from?

Could I do a Bill Whitman in my greenhouse? Meaning, could I remove all of my solid clay, high PH soil and replace with the stuff our plants love? Sure, but it would kill me physically and financially!

Jay, you make a couple good points. First up I think you northerners (and I mean WAY north from my 39S!) are leading the way in tropicals in marginal climates, because you know you need to containerise. People like me in more benign climates keep on planting our mangos and papayas in the ground. Sure they live a while, but never amount to anything and eventually die. ON the Cloudforest forum your collection is one of the best, far outstripping all us 'more favoured' climate guys.

So, it seems ot me that instead of root pruning physically you should do it passively. All that is needed is a permeable sided container. As the roots reach the edges of the pot, they 'air prune' off. The leading tip dies, resulting in a proliferation of secondary roots. This actually results in a far more efficient root system, and is the way the NZ commercial guys do it. Much easier too!

Secondly, how about growing in soil? in NAtural systems there are very few fruit trees that grow in pure organic media. Even the deepest rainforest does not have organic matter levels higher than 50%, and most of the tropical fruit trees thrive in very low C soils. I know one of the biggest avocado nuseries in South Africa uses straight soil with no organic matter at all to grow their stock in. I suspect if you used a beach sand textured soil with an organic/compost mulch, and permeable pots allowing air pruning, both these problems would disappear.

All sounds good but I for one have never seen permeable pots large enough to contain my plants. As for planting in the soil. I would love to. The problem is that I would have to remove nearly all of it due to being only hard-packed clay with a PH of 7+. I would have to dig out a LOT! As soon as one of my low PH loving plants starting hitting native soil, it would start to die. How deep is deep enough? How far out? I'm going to attempt it with a few plants. Lot of work man. This is the one huge negative I see with container growing. I don't know of any good solution to the problem.

Make your own permeable pots by drilling holes in normal pots.

John

I meant planting in soil in pots. 7pH hard clay is not a goer at all obviously. Is it possible to get some sand locally? Sand will not break down like organic media. Sandy loam soil which does not go hard into lumps is better still.

I have 600 acres most of which is based on a structure-less volcanic origin tephra subsoil, of a sandy loam texture, and pH about 6.0. I use this subsoil as my standard potting media, and find most of my plants perform very well in it. It has totally constant CEC, N drawdown is zero, and the aeration properties are totaly consistent. This soil is texturely excellent, but of very low fertility. But it grows beautiful palms with a bit of mineral fert added, and also requires a lot less water than organic media, while still allowing excellent drainage. It should be good for potted fruit trees as well, although I confess readily that I am only just beginning to trial this. Got a 6 foot tall Jakfruit and some baby mangoes and bananas so far.