I have a few big wooden boxes in my covered shed. The shed is built on the south side of my shop. It has plastic sides and polycarbonate top. It works great for growing vegetables when the outside is still cold. I sowed my lettuce in Feb. and have been enjoying them as salads from April to June. I grew the Polar Ice Green Lettuce from New Dimension Seed. It is great, it's a loose leaf type. I harvest the large leaves and leave the plant in the box. They just keep generating fresh leaves.