Best Cold Frames & Mini Greenhouses of 2025: Extend Your Growing Season
The vegetable garden has a cruel rhythm. By the time your tomatoes are ripening, the first frost is three weeks away. Your cold-weather crops bolt in the June heat. There’s a month in spring when the soil is workable but the nights are too cold for anything tender, and a month in fall when you’re still getting beans but the overnight dip kills your basil. A cold frame or mini greenhouse doesn’t fix the seasons. It bends them. A simple glass or polycarbonate box traps solar heat during the day and holds several degrees of warmth through the night — enough to start seedlings 4-6 weeks earlier in spring, harden off transplants without shuttling trays in and out, protect tender plants from late frosts, and stretch the harvest 4-6 weeks into fall. For the price of a decent pair of pruners, you can add two months to your growing season. ...