Ferry Morse Jeffy Seed Starter Greenhouse 50 contains fifty 1- 3/4 inches square cells in 1 Jiffy-Strip. It measures 11 inches x 22 inches in a reusable tray and dome made from recyclable plastic. Clear dome maintains greenhouse humidity and temperature for healthier seedlings. The seed starter is 100 percent biodegradable, peat pot strip, made of Canadian sphagnum peat moss and wood pulp, provides a rich, high-quality growing environment and can be planted directly in ground or larger containers to minimize transplant shock. Use with all Jiffy planting mixes.