Greenhouses are a gardener’s best friend. They allow us to grow to our heart’s content, rain or shine and even grow a variety of plants which our own climate would not normally tolerate. Despite their plentiful benefits and peaceful, serene setting, many gardeners will know the struggles of managing a greenhouse through winter.
Many gardeners will opt to stop using their greenhouse during the winter months, but this doesn’t have to be the case. With a variety of greenhouse insulation products available, your plants can grow safely throughout the winter season.
Whether you’re an adept agriculturalist or a budding bloomer, here’s how you can stave off the winter frosts to really get the most out of your greenhouse.
The seasons and how they affect your greenhouse
By utilising light, temperature and humidity, greenhouses have been used as a reliable way to grow plants for hundreds of years. However, what do you do once the temperature drops and the deadly frosts begin to descend? Most plants simply can’t cut it in the face of adverse weather conditions, which is why your greenhouse needs to be prepped perfectly to shelter them from those icy, wintery winds.
During the winter months, light and warmth are scarce, with daylight hours being drastically reduced and temperatures often falling below freezing. Your once tropical sanctuary has just turned polar, but don’t worry, there are plenty of steps you keep your plants cosy and thriving, despite the weather outside.
Fighting the frost
If you wish to use your greenhouse throughout the winter, you’ll need to prepare. As a general rule, a greenhouse’s internal temperature usually hovers several degrees above the outside temperature. Obviously this can vary depending on factors such as light, shade and ventilation, but roughly, this is what can be expected. The problem arises during winter months, particularly in cold climates, where the temperature drops below freezing. Despite your greenhouse conditions being somewhat warmer than those outside, plants will rarely be able to survive here without some help.
Nowadays, there exists a vast number of greenhouse insulation products to help you to combat the cold but most traditionally, many opt to use bubble wrap insulation. This can prove to be extremely effective at retaining heat but also allows light to filter through, ensuring that plants are still easily able to photosynthesise. An additional benefit of this is that, especially in comparison to other methods, bubble wrap greenhouse insulation can be a reliable and cost-effective method of maintaining your greenhouse. Though you may need to dedicate some time to install this, the required effort to do so is relatively low and requires minimal knowledge to implement.
Another method of choice when it comes to heating your greenhouse throughout the winter months is through the use of specialist greenhouse heaters. These products act as an effective and convenient way of heating your greenhouse during cold spells but some models can also be used throughout the warmer months to circulate air using their built-in fan systems.
The obvious downside to these products is cost, as these can require an initial investment to set up, however, this cost can be easily justifiable to many gardeners, particularly considering the numerous benefits which running a greenhouse year-round can grant, namely the cultivation of fruit, vegetables and other useful plants. Additionally, many models operate in a manner which minimises energy consumption so the products themselves tend not to be costly to run and this can also help to justify any initial costs spent.
For an added level of protection, some gardeners also opt to use horticultural fleece. These can be easily hung over plants for an added layer of protection against the cold. Gardening know-how describes horticultural fleece as “a synthetic material, made from polyester or polypropylene, [which] is more like a fabric than plastic... Garden fleece is lightweight, soft, and warm” making it the perfect insulator from harsh weather conditions.
Each method of greenhouse insulation is useful and successful in its own right but for a truly temperate greenhouse through the winter months, a combination of all 3 would undoubtedly be the most effective.
While each method has proven results when it comes to battling frost, it really all comes down to the plants you choose to grow, timing and your budget. Particularly sensitive plants may require additional support to survive the winter, while hardier plants may do fine with just one of the solutions mentioned.
Whatever your choice of greenhouse insulation, winter gardening doesn’t have to be a pain. Select the right tools and your harvests will continue to be plentiful, but if you’re still unsure of what to do, why not check out our winter gardening guide to help you keep busy in the garden and choose the plants which are best suited to survive the season of frost.