Tomato Growing in Polytunnels
Polytunnels are a budget-friendly way to extend your tomato season, protect plants from bad weather, and produce bigger, sweeter crops. Here’s everything you need to know for polytunnel tomato success—from setup to harvest.
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Why Grow Tomatoes in a Polytunnel?
- Warmer Climate:
Extends the growing season, allowing early planting and late harvests. - Rain Protection:
Reduces risk of blight and leaves stay dry—less disease! - Consistent Environment:
Easier to manage temperature, humidity, and airflow than outdoor beds.
Setting Up Your Tomato Polytunnel
- Best Varieties:
Indeterminate/vining tomatoes thrive—try ‘Gardener’s Delight,’ ‘Ailsa Craig,’ ‘Shirley,’ ‘Sungold,’ or your favorite cherry and beefsteak types. - Soil Prep:
Dig in compost or well-rotted manure. Renew or change topsoil annually to reduce disease buildup. - Spacing:
18–24 inches (45–60cm) between plants for airflow and easy access.
Leave wide paths for watering and harvests. - Supports:
Use tall bamboo canes, string lines from the roof, or wire trellis—plants can easily reach 6 feet+ in a good season.
Polytunnel Care Tips
- Ventilation:
Open ends/vents daily. Avoid high humidity—polytunnels heat up fast in sun! - Watering:
Consistent watering is vital—tomatoes in tunnels dry out quickly but hate being waterlogged. Drip irrigation is ideal. - Mulching:
Use compost, straw, or grass clippings to retain soil moisture.
Pollination
- Gently shake stems or flower trusses during blooming, or tap supports daily—no wind means less natural vibration!
- Open doors to encourage bees on warm days.
Feeding
- Start high-potash tomato fertilizer as soon as first flowers appear, repeating every 7–10 days during heavy fruiting.
Common Challenges
- Whitefly, aphids, and spider mites can thrive—check plants regularly and use organic controls if necessary.
- Overheating—shade or use whitewash on plastic, ventilate well on hot days.
Harvesting
- Pick fruits as soon as ripe for best flavor and to encourage further production.
- Watch for split fruit after heavy watering—consistent moisture prevents cracking.