I've taken Ed's advise and begun to presprout my next planting of spinach seeds. It has been two weeks since I planted 12 soil blocks with Space spinach, new for 2012 seed, and only four have managed to germinate. I now have another 18 presoaked seeds resting in a damp coffee filter, keeping warm in a plastic baggie on top of a shop light.
Many of February's seedlings have been moved from under the shop lights to the laundry room window. They seem just as happy there, as long as I remember to turn the containers every couple of days to keep the plants growing straight.
Moving some seedlings cleared up a lot of space on the grow shelves for the March plantings. I've decided to go with the 6-pack cells rather than soil blocks this time around, as I can crowd more plants into a smaller space (72 cells per flat vs 36 soil blocks) while waiting for the mini greenhouse in the garden shed to warm up enough that I can move some of them out there.