A garden cover goes by several names depending on its function: cold frames, cloches, row covers, and garden tunnels are the most common terms, each describing a structure designed to protect plants from weather, pests, or temperature swings.
The right term depends on what the cover actually does. A cloche is typically a small dome or bell-shaped cover placed over individual plants. A row cover is lightweight fabric draped directly over a crop row. A cold frame is a bottomless box with a transparent lid — usually glass or polycarbonate — that traps heat around a bed. Garden tunnels use hoops to hold cover material above a longer planting row. Each type addresses a different scale and protection need.
- Cold frames typically stand 12–18 inches tall and use glass or polycarbonate lids to trap ground heat.
- Row cover fabric is rated by weight: 0.5–0.9 oz/sq yd for frost protection, up to 1.5 oz/sq yd for pest exclusion.
- Garden cloches cover a single plant; row covers and tunnels span continuous runs of 10–100+ feet.
- Polycarbonate cold frame lids transmit roughly 80–90% of available sunlight, compared to about 90% for glass.