Hi Skip,
" 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. "
This time of the year is very near to the beginning of Summer. Most people are starting their seeds now by simply planting them in-ground, or they planted their seeds in-ground after the danger of frost was over at the beginning of Spring and they are now caring for their garden(s).
For whatever reasons, capillary beds, and even cold frames, are not used much by gardeners nowadays. This might be a good time to do some experiments with capillary beds for next year. The idea of a system that would care for your plants in your absence on a vacation has its attraction.
ZM
