This low-profile enclosure consists of a transparent glass or plastic top over a wooden or metal base. Growers use it to harden off seedlings before transplanting them into the open ground or to extend the growing season into colder months. The structure traps solar heat and shields tender foliage from frost and wind.
Heard on the job
Keep the frame closed tonight since we're expecting a hard frost before morning.
Insider tip
Always prop the lid open on sunny days, as temperatures inside can quickly spike and bake the tender seedlings.