Many gardeners and smallholders choose not to heat their polytunnels. But if you’re planning on growing throughout the year you will need to provide some heat. The issue of course is that heating a polytunnel can be very expensive.

Heating a large polytunnel would be unfeasibly costly for most of us. And probably impractical too. After all, even a medium sized polytunnel is a massive area to heat.

However, by narrowing the area, it does become possible to heat your polytunnel. Gather your winter plants in as small an area as you can possibly manage. This area then becomes the only part of the polytunnel you need to heat.

How to heat a polytunnel

If you’re planning on heating your garden or allotment polytunnel (or at least part of it) during winter you do have a few options. A combination of these methods should help you keep your plants heated and healthy during the colder months.

Fuel heaters

Paraffin has long been used as a heater for greenhouses and potting sheds. However, paraffin heaters aren’t too powerful and will struggle to heat anything but the smallest area of a polytunnel. Although declining in popularity they are cheap to buy and run.

Gas heaters are expensive but on the plus side they are thermostatically controlled to reduce running costs. Being able to control the level of heat is important for the plants wellbeing as well as reducing heating costs.

An electric heater is probably the least practical type of heater. There won’t be many home gardeners who have an electricity supply running into their polytunnel. Even if you do have mains power in your polytunnel an electric heater is very expensive to run.

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Low-cost ways of heating a polytunnel

Although fuel heaters are expensive there are some low-cost methods you can use to heat your polytunnel.

Horticultural bubble wrap

This is a really simple, but effective, way to heat a polytunnel. Horticultural bubble wrap retains the heat and blocks draughts. But you can’t take shortcuts. Ordinary bubble wrap won’t do the job. You have to use specialist horticultural material. This is very hard wearing and UV stabilised.

You can use the bubble wrap hung around the planting area and to also insulate the doors as well as wrapping around individual pots.

Using bubble wrap is very affordable. It’s also quick and easy to deploy and is far more convenient than using fuel heaters.

Using candles

This sounds really old school (it is) but it’s surprising how effective lit candles are in heating a small space. You must of course ensure the candles are secured. Standing them in a ceramic pot of soil is a great way to do this. You must also ensure there are no draughts.

If you’re not convinced about the heat candles can generate, just think about Christmas and how warm the room gets when you light the festive candles.

Double poly insulation

Doubling up on most things is usually a good idea. And it certainly is in a polytunnel. If you have a small polythene tunnel or cloche you can use it as a very effective form of double glazing by placing it over the winter plants within the polytunnel.

Heating your polytunnel

Heating a polytunnel isn’t easy. Neither is it practical at times. But if you do need to heat a section of your polytunnel in winter then the methods we’ve discussed above should help. Combine two or three of the different methods for the best results.

Where to buy your polytunnel

Here at Direct Plants, we manufacture all our polytunnels in our own workshops. We do of course use our own tunnels on our five-acre nursery. Every polytunnel we make is heavy duty commercial grade quality which means that by buying from us home gardeners can use exactly the same tunnels as professional growers.

Our tunnels are sized from 10x12’ and, because you are buying directly from the manufacturer, you won’t find better prices anywhere. You can learn more about our polytunnels here.