For home and market gardeners. Round cells. Use with Seedling trays for extra support or with Leakproof Trays for bottom-watering. Holes spaced for canopy development. 72 -cell flats are recommended for beets, endive, kohlrabi, lettuce, leeks, onions, parsley, radicchio, and small - seeded herbs and flowers. Compatibility: Use with all Johnny's trays except Shallow Leakproof Trays (white) and Shallow Germination Trays (black).