Polytunnels are a fantastic way to utilise the space in your garden to grow your own fresh fruits and vegetables quickly and safely. But there are some definite does and don’ts when it comes to making the most of that space, and getting the best harvest possible!
In recent years, the use of a home polytunnel has soared in popularity. Homeowners with small and large gardens alike are making the most of their outdoor space by investing in this wonder-product.
The ability to extend the growing season by around 6 weeks, either way, makes polytunnels the ideal choice for families who enjoy having their favourite vegetables on the table for longer periods. But how does a polytunnel work so efficiently? And how does this tie into what should, and shouldn’t, be grown?
What Goes on Behind the Scenes of a Polytunnel?
Steel frames and polythene covers are used to construct polytunnels. This provides a level of protection to growing crops against sunlight; both from high temperatures and high light levels. However, it also intensifies the growing process. Due to the construction, heat enters the polytunnel at a faster rate than it can escape! This heats the soil and plants so crops inside the polytunnel can grow quicker.
Further temperature controls and additional ventilation is then used to optimise the temperature and conditions of the polytunnel. By minimising the effect of harsher winds and slightly increasing the temperature, plants that would have a hard time growing outdoors have a significantly better chance of surviving. However, just as this benefits some plants, it can have a slightly adverse effect on others.
What Should I Be Growing in My Polytunnel?
A polytunnel provides a great environment to grow an incredible assortment, including:-
- Fresh fruit
In fact, the environment is so successful at growing produce that around 80% of the soft fruits grown for retail in the UK are in a polytunnel! Some of the most popular fruits and vegetables that are grown in polytunnels include:-
- Salad leaves
To get the most out of the space and to ensure that plants continue to grow healthily, crop rotation is essential. This will go some way to determining what kinds of fruits and vegetables that you will need to grow to maintain the nutrition levels in the soil. Different varieties of fruits and vegetables require different nutrients to grow. Planting the same crops in the same spot every year will diminish the nutrition in the soil, potentially damaging the growth of your crop or making it grow less efficiently. Making sure that you have a good variety of different crops will ensure that you make the most of your polytunnel throughout the year.
What Shouldn’t I Be Growing in My Polytunnel?
The majority of plants are perfectly well suited to polytunnel growing, but just like outdoor growing, you need to make sure that both the temperature and humidity are well-suited to the crop type. High temperatures will allow some crops to flourish, whilst others will struggle to grow, or won’t grow at all. A great example is the difference between peppers and potatoes.
Peppers require a temperature of more than 12 degrees to grow- while potatoes can thrive at 7 degrees or higher.
This means that seasonal growing should be adhered to, even inside of a polytunnel. While the seasons are extended considerably, it’s not advised to grow any plants outside of their extended seasons. These crops are unlikely to thrive.
As well as paying attention to crop seasons, it is essential that any crops that could damage the polytunnel are not grown inside. This includes:-
- fruit trees that are likely to grow higher than the polytunnel
- plants with thorns that could damage the interior of the polytunnel
A large part of the enjoyment of owning a polytunnel is exploring just what fruits and vegetables grow well in the atmosphere. It’s vital to pay attention to both crop rotations and the seasons. By rotating your crops and growing in season, you’ll have the best chances to optimise your polytunnel all year round.
Sean Barker is the MD of First Tunnels, and is enthusiastic about providing quality gardening supplies to gardeners across the UK