At just under 8 feet long each, the three shelves will allow us to tend 24 trays at a time of onions, leeks, peppers, tomatoes, and eggplants (plus Sharon's flowers) in the house. In another month, as the risk of super-low temps falls, we'll move the seedlings out to the benches in the 15-foot by 20-foot half hoop house on the back of the shop. Despite having purchased a propane heater with the half hoop two years ago, we haven't actually heated it, yet. Instead we've used old 4-gallon jugs from Greenstar filled with rainwater to collect heat during the day, then radiate it back out in the evening, as the air temperature falls. We cover the trays at night with plastic or row cover as further insurance against chills the more tender seedlings might not tolerate. Someday, we'll deploy a 336-square-foot solar hot water heating array to warm a larger tank of water, but locating a pump and drain-back system (to prevent freezing in cold evenings) still languishes on my "to do" list.
But for now, I'd better go finish hanging the lights. Sharon is itching to start planting her new flower seeds.