I agree, interesting thread, and I'll throw in my two cents for what it's worth. I grow almost all my plants in band pots, those square pots with narrow strips of plastic running from side to side dividing the bottom into four squares. I use a fairly gritty soil mix, so to keep it in the pots, I cut a piece of artists' plastic canvas to fit the bottom. This provides drainage for nearly the entire bottom footprint of the pot. I have built raised beds on a concrete slab (used to be a basketball court) that has most of the plants in them. All the pots are then bedded in sawdust (I use pine, easily acquired here in the northwest at feed stores). I make sure that there is at least a centimeter of sawdust between the bottom of the pot and the underlying surface. The sawdust wicks the water away from the pots since it is easy for the soil and sawdust to contact each other through the thin, porous canvas. As a bonus, the sawdust offers cold protection, and helps keep the plants cool and the roots damp in summer. After three, or sometimes four years, the sawdust has broken down enough that it stays soggy, and must be replaced. The old sawdust is great on the compost pile, mixed with available greens and other brown ingredients. This works as well for larger pots, with the bottom holes on the sides of the pots. Dave Brastow Tumwater, Washington USA, where the above is being tested this week by day temperatures near freezing and nights down to -16 to -12 F ( 8 - 10 C).