The polytunnel has an air-bubble layer under the plastic layer, which helps to keep warm air inside. Larger bubbles also collect more light, which aids in the heating process. Keeping the tunnel clear of snow during the winter can also help to reduce heat loss by up to 30%.
Heating a polytunnel
A polytunnel is a great way to extend the growing season and protect plants from the elements. It can be used to grow out-of-season plants year-round and can be heated in winter. Plants need four basic elements to grow and stay healthy: water, sunlight, heat, and air circulation. Low temperatures slow down this process.
One of the most efficient ways to keep a polytunnel warm in winter is to use bubble wrap. The bubbles in the bubble wrap help retain heat within the planted area. You can even use horticultural bubble wrap, which is extra hardwearing and UV stabilised. This will prevent cracking in ceramic pots and also help to keep the tunnel insulated.
Another great way to keep your polytunnel warm in winter is to use heat sinks. These can be black for maximum solar gain, or filled with water to trap the heat. Heat sinks help keep your polytunnel warmer in winter, and you can place them closest to your plants. It is also useful to have a thermometer in your polytunnel so you can adjust the temperature accordingly.
Using a cloche
Using a cloche to protect seedlings and young plants during the winter months can be an effective way of reducing the risk of frost damage. A wire or plastic frame with clear plastic sheets can be fitted over the seed bed, and a row cover can be fixed to the top and sides. It is essential to remove the covering in the morning to let in light.
The cloche can be made from polythene or other material. In addition to providing good protection from frosts, it also provides extra warmth, keeping heating bills down. Cloches can also be used on a flower bed or veg patch. In order to increase the temperature of your polytunnel, you can also light a few candles inside it.
Proper ventilation in a polytunnel is crucial to your crops’ growth and development. Insufficient circulation can lead to inconsistent conditions throughout your tunnel or greenhouse. This can be seen as hot or cold spots, condensation, or high or low humidity. You can also watch for leaf movement to determine air flow. Keeping one or both doors open can help keep the tunnel well-ventilated.
Ventilation is an important part of a polytunnel’s overall climate control and can help prevent disease. When it is too humid inside the polytunnel, mildews and moulds can thrive.
Plant protection from frost
Plant protection from frost is a key part of winter gardening. Frost can damage plant tissue, including leaves, stems, and flowers. It also ruins the soil beneath the plant, preventing the roots from absorbing moisture. It is especially important to protect young plants from winter frosts.
Proper protection against frost can help to prolong the life of your plants. A polytunnel or mini greenhouse can keep out the cold and trap heat around the plants, protecting them from damage from winter frosts. British weather can be unpredictable, and sudden frosts can easily damage your plants.
Frost is often an issue in polytunnels in winter, and plants can be severely damaged if not protected against it. During this time, you can purchase traditional polytunnel heaters from First Tunnels to help protect your plants against frost.
Crops that can be grown in a polytunnel
If you want to extend your growing season, a polytunnel is an excellent solution. Unlike greenhouses, which use pot-grown techniques, polytunnels have a large soil volume, which allows them to grow plants more consistently. In addition to extending your growing season, polytunnels can be used for plant propagation, bare-root transplant raising and more.
Cucumbers are an excellent crop to grow in a polytunnel. They are a hardy plant that is ideal for late summer and early autumn. The plants can be started indoors in trays or propagators and then transplanted to their permanent site when they are ready.
While polytunnels are not suitable for growing all plants, many of them can grow well in smaller ones. In fact, even a 5-m2 garden tunnel can grow enough vegetables for your family’s needs. However, it is important to know the season in order to ensure the best yield.