Edna said:TylerStewart said:Bigger pots will have much better growth than smaller ones.... I have 30-40 cactus growing in pots (knowing that I was going to be moving when I planted them, I didn't want them all in the ground). I also planted some in the ground at the same time, and the in-ground ones are growing significantly faster. I assume it's just much more room to expand the root systems. The bigger pots I used are also growing faster than the smaller ones, so go as big as you can.
As far as getting pots, at least around here, most landscape companies save up the cheap black pots and can trade them in to the nurseries for a credit. A friend of mine runs a landscape company, and has huge piles of the black buckets, and he said the nursery gives him something like a 40 cent credit towards more plants, so he'll happily sell them to me for 40 cents each cash. If you know a landscaper, check with them. They're ugly, but if the intent is to produce cactus, it makes no difference.
I really doubt the soil conditions would matter.... We have bad soil here from a plant growth standpoint, but they do just fine. In pots, I use a 50-50 manure and "reject sand" mix (basically crushed leftover rocks and soil that they turn into a generic sand) that has zero fertility value and it grows well in this mix.
I just want to say that I am thrilled to hear that those black pots are being recycled! I have a whole pile of them in my garden shed so now I just have to find a way to reunite them with a nursery somewhere.
Offer them on Craigslist.