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Food growing · Design beds, crops and systems · food-10Choose protected cropping
Decide whether you need row covers, cold frames, a high tunnel (polytunnel), a greenhouse, or a shade house. Each step up costs more and needs more management.
How
- Row covers and low tunnels: lowest cost. NC State notes about 4 to 5 degrees F (2 to 3 degrees C) of frost protection and some insect exclusion.
- Cold frames: low boxes with clear lids for early seedlings and winter greens. NC State advises a sunny, sheltered spot, no more than 1.2 to 1.5 m wide.
- High tunnels: unheated walk-in hoop houses with roll-up sides. SARE notes they cost less than greenhouses but are labour-intensive, and multi-bay tunnels usually cannot carry heavy snow.
- Greenhouses: heated or ventilated with fans, for year-round growing. They need a power supply for fans, which feeds the power module's load audit.
- Shade houses: for hot climates. University of Delaware suggests about 20 to 40% shade for vegetables, around 30% most commonly; white or aluminised cloth may cool more.
- Check whether your local planning rules treat a tunnel or greenhouse as a structure needing a permit (see legal module).
Do these first
Sources
- Extension Gardener Handbook, Appendix E: Season Extenders and Greenhouses. NC State Extension, accessed 2026-11
- High Tunnels and Other Season Extension Techniques: An Overview. SARE (Sustainable Agriculture Research and Education), accessed 2026-11
- Shadecloth for Hot Season Vegetable and Fruit Production. University of Delaware Cooperative Extension (Weekly Crop Update), accessed 2026-11