#25. Growing Vegetables in a Polytunnel
Polytunnels are a great way to extend the growing season for vegetables and fruits. A polytunnel allows you to grow vegetables whose season is over or varieties that are not native to your region. The tunnel provides protection from the weather and a shelter to nurture seedlings. Setting up and maintaining a polytunnel will require time and effort, but it certainly pays off.
What is a polytunnel: the most basic explanation would be a large framework covered with polythene plastic. The plastic traps energy from the sun, increasing the temperature inside the tunnel. The polythene is specially treated to resist damage caused by the sun's UV rays. It comes with a thermal, anti-fog cover that prevents moisture from banding together to form large drops that block out sunlight.
The aesthetics of a polytunnel are up for much debate. Some people believe that a polytunnel does not look as good as a greenhouse does. Well, beauty does indeed lie in the eye of the beholder, so it is really your choice to make.
The advantages in setting up a polytunnel for your vegetable garden include:
• Retains heat to boost plant growth
• Protects plants from frost
• Provides a warm, sheltered environment for the plants in bad weather conditions
• Protects seedlings and young plants, helping them grow healthily for transplantation
The main disadvantages to growing your vegetables in a polytunnel is that an irrigation system has to be established, but then again, any vegetable garden needs water! And the second problem is diseases and pests tend to flourish in an enclosed space.
When selecting the size of the polytunnel for your vegetable garden, factor in companion planting and planting species that attract the beneficial pests your garden needs.
Siting the polytunnel is important; avoid areas where water collects, a water logged tunnel is plain useless. You need to locate the tunnel in a spot that gets the most sun, but will not face the brunt of high winds.
Plan for water and electricity to be laid on in advance and if you use raised bed gardening method, complete the beds before adding the tunnel. Make sure you plan your beds in a way that avoids the plants getting crushed up against the plastic when fully grown.
If you live in an area where the water pipes freeze in winter, bury the pipes about 18 inches into the ground with a stand pipe in the tunnel. Alternatively, set up a trickle system inside the tunnel.