These growing trays (with drain holes) are formed from dense paper and is perfect for microgreens and wheatgrass. They are intended for a single use and are fully compostable. They resist water and will hold their shape well for a single grow. The trays measure approximately 19" long by 9 inches wide and has a shallow depth of approximately 1.5 inches. It nests inside a standard 10x20 inch drip tray with plenty of room to spare.