Comparing Cold Frames, Hoop Houses, and Greenhouses
The short answer
These three structures trade cost and simplicity for control. A cold frame is a small, unheated, box-like structure with a clear lid that sits on the ground. A hoop house (high tunnel) is a larger, walk-in, usually unheated structure of plastic stretched over bent pipe. A greenhouse is the most permanent and controllable, often with heating and powered venting for year-round growing.
Cold frames and hoop houses rely on trapped solar heat and cost little to build and maintain, making them ideal for extending cool-season crops. Greenhouses offer the most control over temperature and can grow tender plants all year, but they cost more and require more maintenance and often electricity.
At a glance
- Cold frame: small, unheated, low box with a clear lid; lowest cost and maintenance; extends cool-season crops a few weeks
- Hoop house / high tunnel: larger, walk-in, usually unheated; solar-heated; more season extension and growing space
- Greenhouse: permanent, often heated and vented; most control; supports year-round and tender-plant growing at higher cost
How to choose
Pick a cold frame for the cheapest way to start and finish the season a few weeks early or late. Choose a hoop house for more room and stronger unheated protection. Choose a greenhouse when you want full climate control and year-round growing and can accept the cost and upkeep.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- University of Georgia Extension — Extending the Crop Season: Unheated Spaces (C1027-14) — Compares unheated cold frames and tunnels for season extension.
- University of Minnesota Extension — Extending the growing season — Cold frames and tunnels are unheated, solar-warmed structures for cool-season crops.
- NC State Extension — Appendix E. Season Extenders and Greenhouses — Distinguishes cold frames, tunnels, and greenhouses by structure and control.