Has anyone personally compared capillary mats vs. periodic bottom watering by hand? I am considering making a large capillary bed, which is similar to a capillary mat, to place in a large cold frame (4ftx10ft) but dont want to waste a lot of time and effort if constant bottom moisture isn't likely to work well. In its simplest form a capillary bed would be something like a cheap kitty litter pan with an overflow hole in the side 2" from the bottom, then filled with 3-4" of washed sand. You would fill the pan with water until water drains out of the hole, creating a water table 1" below the surface of the sand, then you would place your flats, pots, or plug trays on top of the sand, and the idea is water will wick up into them. The better designs have inverted water bottles all the way up to automatic valves or float valves to keep the water level constant. The capillary beds can be scaled up to large nursery beds, and the height of the water table can be adjusted to be further from the surface of the sand for plants that like it dryer.
http://depts.washington.edu/pr...
https://agsci.oregonstate.edu/...
Should I try this for the twenty 1020 deep plug trays I have, or would I be better off trying to make a large pan or pans to bottom water and then drain by hand? I am attracted to the capillary bed design because I can connect it to a rain barrel and not have to worry about it drying out while I'm at work or away on vacation.
I don't have any space for seed starting other than an unheated somewhat wet cellar, and I'd rather not use electricity for lights, heating mats and climate controls if nature can do some of the work for me in cold frames at different times of the year.
