Hi Carol. Long time no see.
Love what you are doing to teach the kids. Heavy duty garbage bags would work, 5 gallon buckets would be the easiest to move around once planted. Drill a few holes in the bottom for drainage, they come with a handle.
Check with restaurants, fast food places, etc. Let them know what the buckets would be used for. The mild jugs would be great for smaller type crops.
With the buckets the kids could take their planted project home at the end of the week.
