PVC hoop house (low tunnel) over raised beds

A hoop house or low tunnel is a semi-circular structure of bent PVC pipe or metal hoops covered with greenhouse plastic or row cover fabric, extending the growing season by 6-8 weeks. It is more versatile than a cold frame because it accommodates taller plants and is easy to remove seasonally. Build hoops from 1/2-inch PVC pipe cut to 8-10 foot lengths (for a 4-foot wide bed), bent into arches and inserted into 1/2-inch rebar stakes driven 12 inches into the ground on each side of the bed. Space hoops every 3-4 feet along the bed length. Cover with 6-mil greenhouse plastic (for maximum heat retention) or medium-weight row cover fabric (Agribon AG-30 or AG-50 for frost protection to 24-28 degrees F). Secure plastic with clips, sandbags, or by burying edges. For ventilation, push plastic up from one end on warm days. A complete hoop house setup for one 4x8 bed costs $25-50 in materials. In cold climates (zones 3-5), combine the hoop house with an inner layer of floating row cover for double insulation, extending protection to single-digit temperatures for cold-hardy crops. Replace plastic every 2-3 seasons as UV degrades it.