It may work for a while...then run out of gas as roots completely colonize all available soil/medium in the pots. Any reason planting in soil is not an option?

thanks for the info... I cant plant in soil because I have no yard/grass but I have a rooftop terrace so I have to use containers.

thank you so much for the plethora of info! I'll start with the search and scour other parts of the site :)

If you do elect to go containerized-and now I understand your reasons for doing so-pay attention to the medium you use in the containers. Simply put, these plants are going to have to remain in the same stuff for years, and therefore, it will be important to follow the "Al's Gritty Mix" type of medium, since it must last more than one growing season.

I got blasted on that silly forum for having the gall to state the obvious-that this type of mix only really matters where plants must remain in the containers for more than one growing season-in other words, not annuals. Nor were my words hypothetical; I've produced amazing containerized displays for ever 25 years now. I'm pretty sure I know what I'm talking about, lol! But the regulars there would have none of it. So you know what I did? I left. Who needs the grief? I've got a web presence larger and more meaningful than most of the amateurs on that board (nothing wrong with being an amateur) so when all the armchair psychologists started coming out of the woodwork to diagnose my problems.....hehe, the rest is history!

But for your purposes, this does matter. Use a mix similar to what is described there. You need chunky stuff in there for good drainage and you need stuff that won't break down so fast that it loses its chunky nature. There's actually quite a bit more to it, but I'll let your fingers do the walking.

Al's gritty mix is a houzz contributor ...

the problem i see with it.. is by the time you make your own .. you will have a truck full ... lol ...

with trees ... you want the plant to get a sip of water [after properly wetting it in the first place] ... and then full drainage ... no standing or retained water ... which is kinda not in line with your self watering pots ...

and the way you get that... is to have large particles incorporated into the base media...

the simplest way to see this... is to look at cactus media ... below is AN EXAMPLE of coarseness .... not that you need to do this.. compare this with Al's formula ... between the two concepts ... you can learn all about drainage.. and particle size ...

ken

http://lophophora.blogspot.com/2009/09/recipe-for-cactus-soil-mix.html

http://www.gardenweb.com/gardenweb/query/als-gritty-mix

I'm not going to review all that just now, but the main concept about soil particle size and how that affects drainage is that the course particles must make up a sufficient percentage of the mix that they actually lodge against each other. A few grains of course sand in an otherwise finely-textured mix will do nothing to aid drainage. they must lodge against each other to form the relatively large pore spaces that are what allows for good drainage and soil aerification in the first place. Otherwise, you end up with a bowl of pudding with a few marbles in it. Not my analogy but I saw it here somewhere, so I swiped it!

So, in the case of folks thinking that "adding a little sand" to the mix will make their garden soil drain better....uh uh, ain't gonna work. You would need to add up to 70% sharp builder's sand to get to that magical point where the individual sand grains are lodged against one another. 70%!

My wife grows orchids and she uses some kind of potting mix that basically has no soil, its a lot of wood/bark chips, but its highly porous/lots of space in. Im assuming this is the same kind of concept for these trees in containers? I want good drainage but moist underneath?

Yes, you are correct, JJ. Pine bark chunks are a common ingredient in such mixes.

I use a mix of almost pure woodchips. I mix well decayed with chips that are relatively new. It's good for two years before decaying to the point it gets mushy, then I either pot up or plant it in the ground. No fertilizer is needed, but I'm not a commercial nursery that needs to force as much as possible out of each plant.

mike