Cloches Needed
12
Cost
$96
Coverage
21 ft²
Plants
12
Wall O' Waters Needed
12
12 plants protected
Total Cost
$96
Coverage
21 ft²
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Inputs
Result
12 plants × 1 cloche each = 12. Cost = 12 × $8 = $96. Coverage = 12 × pi × (9)² / 144 = 27 ft².
Inputs
Result
24 plants × 1 bottle each = 24. Cost = 24 × $0 = $0. Coverage = 24 × pi × (3)² / 144 = 5 ft².
You need one cloche per plant for individual covers (bell jars, Wall O' Water). For row tunnels, you need one continuous cover per bed row. If you have 12 tomato plants spaced 18 inches apart, you need either 12 individual cloches or an 18 ft row tunnel.
Wall O' Water is the best cloche for tomatoes. The water-filled tubes absorb daytime heat and release it at night, protecting plants down to 16°F. This allows planting tomatoes 4–6 weeks before the last frost date. Each Wall O' Water costs about $8 and lasts 3–5 seasons.
Glass bell jars protect to about 24–28°F (4–8°F of protection). Wall O' Water protects to 16°F (20°F of protection). Plastic bottles provide about 4°F of protection. Row tunnels with medium-weight fabric protect to 24°F.
| Cloche Type | Protection | Light | Cost Each | Durability |
|---|---|---|---|---|
| Glass Bell Jar | to 24°F | 90% | $25 | 10+ years |
| Wall O' Water | to 16°F | 80% | $8 | 3–5 years |
| Plastic Bottle | to 28°F | 80% | Free | 1 season |
| Row Tunnel | to 24°F | 70% | $3/ft | 2–3 years |
Remove cloches when nighttime temperatures stay above 50°F consistently (usually 2–4 weeks after last frost). Remove gradually — vent cloches for a few days first by propping them open, then remove completely. Sudden removal can shock plants.
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Last Updated: Mar 19, 2026
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