The Super Sprouter� Root Raft� floating plug tray is designed to be a self-watering starter tray. Root Raft� includes a 10 x 20 in tray for holding water and a styrofoam 55-site floating insert loaded with Super Sprouter� custom-blended and custom-sized grow plugs. Mother Earth� BioChar is added to this exclusive formulation. No worries about watering�moisture is automatically wicked through the plugs. Just fill the tray and walk away. If you desire a mini greenhouse effect, you can use any of the Super Sprouter� domes to get the job done. Domes sold separately.