We planted in all kinds of containers this year, even an old plastic toolbox from a pickup truck bed, an old metal horse trough, some old
wood we found,
milk crates lined with garden paper became awesome strawberry lettuce beds. One thing we will never do again is buy peat moss. If you don't keep things watered and forget or it dries too much during the day that shit turns into a brick, it isn't fun to deal with and we have read many horror stories about the stuff. There are many alternatives, they're all better. As far as containers though, just about anything will grow in a container, even
trees.