9GreenBox - Seedling Starter Trays, 216 Cells: (24 Trays; 9-cells Per Tray), Plus 5 Plant Labels Drain holes at bottom of each cell. Top Quality offer by 9Greenbox. Includes five plastic plant labels! (5" long). Each cell measures 1.5" square by 2.25" deep. 216 cells, (will ship as 24, 9-celled trays). Equivalent to THREE 10x20 "flats" Ideal cell size to transmit room temperatures for optimal root growth.