Growing tomatoes in a polytunnel can significantly boost your harvest, offering better control over the environment and extending the growing season. With the right setup and care, you can enjoy vibrant, juicy tomatoes that thrive in the protective space of a polytunnel. Here's a detailed guide to help you get started.
Why Use a Polytunnel for Tomatoes?
Polytunnels offer a unique advantage for growing tomatoes:
- Extended Harvest Season: Plant earlier in the spring and continue well into late autumn.
- Weather Protection: Shield your crops from heavy rain, wind, and unexpected cold snaps.
- Pest and Disease Control: While not entirely pest-proof, a polytunnel helps minimize exposure to certain pests and diseases.
These benefits make polytunnels an ideal choice for anyone looking to grow healthier and more productive tomato plants.
Step 1: Preparing the Polytunnel
Choosing the Right Size
A good-sized polytunnel ensures your plants have room to grow. A minimum height of 6 feet is ideal for tall varieties, with enough width to allow for proper spacing and ventilation.
Soil Preparation
Tomatoes thrive in fertile, well-draining soil.
- Mix compost or well-rotted manure into the soil before planting.
- Check the soil pH and aim for a slightly acidic level between 6.0 and 6.8.
For container growing, choose a high-quality potting mix designed for vegetables.
Ventilation Matters
Good airflow inside the polytunnel is critical. Poor ventilation can lead to fungal diseases and overheating. Install vents or roll-up sides to allow for easy temperature regulation.
Step 2: Planting Tomatoes in a Polytunnel
Choosing the Best Varieties
Select varieties that thrive in the controlled environment of a polytunnel. Indeterminate varieties like ‘Moneymaker,’ ‘Ailsa Craig,’ or the ever-popular ‘Sungold’ are excellent choices.
When to Plant
Start seeds indoors 6-8 weeks before the last frost. Transplant seedlings into the polytunnel once temperatures remain consistently above 50°F (10°C).
Spacing and Depth
Proper spacing is crucial for healthy growth:
- Plant seedlings 18-24 inches apart to ensure airflow.
- Bury the stem deep to promote a robust root system.
Step 3: Caring for Polytunnel Tomatoes
Watering
Tomatoes need consistent moisture.
- Water deeply 2-3 times a week.
- Avoid wetting the leaves to reduce the risk of fungal diseases.
Drip irrigation systems or soaker hoses work well for this.
Feeding
Once your plants start flowering, switch to a tomato fertilizer high in potassium to encourage fruiting. Feed regularly to keep the plants healthy and productive.
Supporting and Pruning
- Use stakes, cages, or string to support your plants as they grow.
- Prune side shoots (suckers) to focus energy on fruit production.
Step 4: Managing Common Challenges
Temperature Control
Tomatoes thrive in temperatures between 70-85°F (21-29°C).
- Use shading during heat waves.
- A small heater can help maintain warmth during cooler nights in early spring.
Pest Control
Although a polytunnel reduces pest problems, some may still find their way in.
- Introduce beneficial insects like ladybugs to control pests naturally.
- Neem oil or insecticidal soap can help with aphids and whiteflies.
Disease Prevention
Prevent fungal diseases by ensuring good airflow and keeping leaves dry. Rotate your crops each year to avoid soil-borne pathogens.
Step 5: Harvesting Your Tomatoes
Polytunnel-grown tomatoes often ripen earlier and have better flavor.
- Pick the fruits when they are fully colored and slightly soft.
- Regular harvesting encourages more fruit to develop.
Why Polytunnel Tomato Growing is Worth It
A polytunnel offers an efficient and productive way to grow tomatoes, providing control over the growing environment and ensuring a successful harvest. With careful planning, attention to detail, and consistent care, you’ll be rewarded with delicious tomatoes that taste far better than store-bought varieties.
Enjoy the process, and happy gardening!