If you go into your local supermarket and look at there cut flowers you will notice they are in a plastic bucket about 10" across and about the same deep with no holes in them , I use these for growing toms / peppers in and put a ring of holes about 3" up from the bottom to make a 3" water table in the bottom.
I know my local somerfields and coop will give them away if you ask , but sometimes they ask for a donation into a charity box. :o :o