Yeah I have always used square pots- starting with 3", then 1L/4.5", then 1 Gallon (all I could find were these rectangular waste baskets), then for the monster beeyatches, 3 gallon, 12"x18" pails scrounged from restaurant dumpsters, yuck. But when I had WAAAY too many plants it WAS nice that those pails have wire handles on them.