It's been awhile since I've visited this forum but I'll try to answer your question. First of all, could you tell what plants that you want to plant in buckets? If I know the exact plants, I can give you a better answer.

Scott

Thanx for responding, Scott.
Maybe I should have explained that I'm not doing the traditional bog as discussed most of the time on this forum. All I want to do is grow perennials that require more moisture than most of the plants in my perennial borders. Things like lobelia, trolius, astilbe, tradescantia (spiderwort), swamp hibiscus, etc. Also, want to try some others such as lupines and asclepias which always die on me & wonder if they don't get enuf moisture.