Gallione, in his position as Technical Services Technician in the research department at Johnny’s Selected Seeds in Maine, is used to answering gardeners’ questions. I started at the beginning with mine: Why grow crops under cover, anyhow?There are two basic uses for fabric row covers, Paul explained:To modify temperature (for heat retention or frost protection, most early and late in the season with heavyweight fabrics); As a barrier to keep out insects, crows, and chipmunks, to name a few common troublemakers. (Note: You can also create some shade, perhaps for summer salads—t