Plug Inserts 6 Cells Each One Insert is recommended for all seeds. With drainage holes. Cells are 2 1/2 inches square by 3 inches deep. Inserts are made from BPA food safe recycled plastic. They are wider at the top and taper down a bit to allow for easier removal of seedlings. Use a bottom tray to water the seeds in the pots so you do not dislodge the seed by top watering. With a good germination mix, the right amount of water will be absorbed for proper watering. I use these in my greenhouse to start seeds. Generally good for one use.