Frost Cloth Coverage Calculator
Calculate how much frost cloth or row cover you need to protect garden beds and plants from freezing temperatures.
Frost Cloth (also called row cover or garden fleece) protects plants from frost damage by trapping heat radiating from the soil. Proper sizing includes drape allowance so the cloth reaches the ground on all sides.
Formula:
Cloth width = Bed width + (2 × Drape) + (2 × Plant height)
Cloth length = Bed length + (2 × Drape)
Total area = Cloth width × Cloth length
Where Drape is the extra material needed to reach the ground and be secured (typically 6–12 inches / 15–30 cm on each side).
Frost Cloth Weights:
| Weight | Protection | Best For |
|---|---|---|
| Lightweight (0.5 oz/yd² / 17 g/m²) | Down to 28°F (−2°C) | Light frost, insect barrier |
| Medium (1.0 oz/yd² / 34 g/m²) | Down to 26°F (−3°C) | Moderate frost |
| Heavy (1.5 oz/yd² / 51 g/m²) | Down to 24°F (−4°C) | Hard frost |
| Extra heavy (2.0 oz/yd² / 68 g/m²) | Down to 20°F (−7°C) | Severe frost, winter use |
Standard Roll Sizes:
- Common widths: 6 ft (1.8 m), 10 ft (3 m), 12 ft (3.7 m)
- Rolls typically come in 25, 50, or 100 ft (7.6, 15.2, 30.5 m) lengths
Practical Example: A raised bed 4 ft × 8 ft (1.2 m × 2.4 m) with 18-inch (45 cm) tall plants:
- Cloth width: 4 + (2 × 0.75) + (2 × 1.5) = 8.5 ft (2.6 m)
- Cloth length: 8 + (2 × 0.75) = 9.5 ft (2.9 m)
- Total area: 8.5 × 9.5 = 80.75 sq ft (7.5 m²)
Metric/Imperial Conversions:
- 1 yard = 0.914 m = 3 ft
- 1 sq yard = 0.836 m² = 9 sq ft
Tips:
- Secure edges with stones, soil, or garden staples to prevent wind from lifting the cloth.
- Lightweight covers can rest directly on plants. Heavy covers may need support hoops.
- Remove covers during the day for sun exposure and pollinator access (unless temperature stays below freezing).
- Frost cloth can be reused for several seasons if stored dry.
- For individual plants, calculate the circumference and height to size a plant wrap instead.
- Water the soil before covering — moist soil releases more heat overnight.