Almost anything will work for your application. You could even use 40% garden soil, 40% sand, 20% compost. The earth will act as a giant wick, so perched water in a soil comprised of small particulates won't be a problem. Soils with a high mineral content will help prevent shrinkage.

Yes, you're talking more about in-ground gardening in a raised bed than container culture. The main difference will be the higher root temps associated with a container.

Al

Thank you Al. I appreciate your advice and all the useful information that you have posted here over the years. I'm glad that I found this forum. I've been growing veggies in raised beds and containers for a few years, but this will be my first attempt at growing trees.

Michael

I think that I am going to do the same as michael. I have several other question that I would be grateful to find the answers to. Would overwintering require anything different, besides the mulching? Would I need to wrap the container? Also I have bought some trees and I'm not certain the size of the containers that I need to get or if the smart pots would be best in those situations. So, I'm going to list them and if you have any answers or ideas that would be helpful and hopefully I can order, before my shipments get here!
highbush bluberries 4-6 feet
Columnar Apples 8 feet
Dwarf stella cherry 10 to 12 feet
Currants ?

I have read about someone successfully growing the blueberries in 20 inch containers for 5 years, but I only have found the recommendation to put the apples in half wine barrels. And I'm certain that the cherry tree needs to be in something large as well. So I would like to know what size you recommend and if you not would recommend smart pots for any of these particular fruit trees.
Thanks for all of the great information and for any help you can offer.
Rachelle

Mulching, primarily as insurance against dessication in your zone, should be all you need do, and wrapping is unnecessary.

If you have the smart pots setting on soil, there is no limit to how large you can go with the container size. The earth will act as a giant wick & remove all the perched water, so you'll actually be growing in a raised bed, rather than a container. That may seem like a small technicality, but it isn't. It makes quite a difference and is more than a bit of a departure from any advice I'd give about an appropriate size for a conventional container.

Al

I have no experience with Smart Pots but considerable experience with roots. Will a fabric bottom really keep roots from growing through the fabric into the ground? Weed barrier fabric, and I have used several types, is not 100% in preventing root penetration. Al

Al thanks for the info.
That definitely helps me let go of my wintering concerns. I have decided that 20 gallon containers is enough for my trees/bushes. I was beginning to think I needed 100 gallon containers. lol! I'm in a town house, that would be very difficult.
Another question is about getting and keeping my soil acidic enough with organic things. I will be using regular gardening soil in the smart pots (unless I'm strongly advised against that). I'm sure that the soil will not be nearly acidic enough and that I'll need to do something.
Do I need to be concerned about the roots coming out of the fabric? and should I do anything about that?
Thanks for the guidance. My trees will be arriving in less than a week, so I'm trying to get prepared and finish all of my research. I really, really don't want any of these trees to die!
Rachelle

First, I have to ask why you're sure the soil pH will be too high? Using a fertilizer that furnishes its N in ammonium/urea form will help lower pH. You could also mix in a 25% pine bark component & leave out the compost to help with pH. Using 30-10-10 fertilizer will help to acidify the soil AND help guard against N immobilization at the same time.

You needn't be concerned about the roots growing through the SP walls/bottom into the soil. It will actually allow the plant better growth. You'll only need to guard against the plant getting to the point that moving it will be difficult because it is anchored to its location. I would probably sever the roots, lift the pots, & rotate 180* each spring until they are planted out.

If you're getting liner-size, bare root material, you might wish to consider keeping them in the fridge & not planting until danger of frost has passed.

Al

BTW, Mike. If I can get trees to grow in stupid buckets, your smart pots are bound to be a sure thing.

Good luck.

Al

I'm not exactly sure why these Smart Pots appeal to me, but I am a rookie just getting started, and have a twist on the questions posed above.

I have a fully hardscaped front yard, 3-4" of pea gravel over landscape fabric over the native soil that used to be a grass lawn. I am looking to grow fruit trees in Smart Pots, placed on top of the gravel, and utilizing a drip irrigation system as much as possible. I will basically be following Dave Wilson Nursery's suggestions for Southern California for low chill varieties of peach, nectarine, plum, pluot, citrus, almond plus some blueberries, pomegranates, and passionfruit.

If I buy 2-3 year bareroot dwarf trees, and have 20 and 30 gallon Smart Pots, what is the best growing medium to start with, Al's 5-1-1 or Gritty or something peaty?

Also, would it be best to leave the Smart Pots on top of the gravel, or to dig the gravel away and have the pots directly on the landscape fabric, or even go as far as to cut thru the fabric and place the pots directly on the soil?

Once I get the growing medium sorted, I will have more questions on watering and fertilizing, but I am trying to read more topics about those first.

I failed to mention location specifics: 90039, in Los Angeles. Sunset Zone 21 as best I can tell. Full sun all day, 3.5' solid redwood fence around yard (not sure if that helps keep the wind away from the base of the pots, or if that is good or bad?)