Super Sprouter Propagation Station Start your growing season early with everything you need in this kit to start your seedlings. It is proven that seeds grow better with ambient temperatures 10-20°F above room temperature. The Super Sprout Seedling Heat Mat® will provide even warm temperatures for your plant starts. The 7" dome will give your plants more room to grow with humidity control. Kit includes: Super Sprouter Seedling Heat Mat® 10" x 21". 72 site Seed Cell Tray Insert. 10" x 20" Propagation Tray. Humidity controlled NGW® 7" Propagation Dome with Vents. Clonex® Cloning Gel packet.