Carrying Tray Insert for 5 Inch Plastic Nursery Pots. This insert is designed to fit perfectly in our 1020 tray (not included) and hold 5-inch pots (sold separately) to help prevent tipping and provide even spacing. This is the perfect tool to make seed starting easier than ever! They are made for greenhouse growers, seed starters, large and small-scale operations. Keep your growing plants upright by stabilizing them with this carrying tray insert.