That's what we did this morning, as I harvested cutting lettuces growing in my sunny dining room window. I still can't believe it worked. I used regular old potting soil (not special seed mix), and the plastic containers strawberries are sold in (save those-they're great for all sorts of things). I improvised a tray from the lid of a plastic storage tub, which worked really well. Danny was thrilled to have little tea-sandwiches with assorted baby lettuces and butter. As the blizzard raced across our lawn leaving a four foot drift directly at the end of the walkway where the car is parked (it is like the Universe knows, and finds the one spot that will require shoveling) I watered my windowsill garden and laughed. Laughed. You take that old man winter.