How to Heat Your Greenhouse in Winter

how to keep your greenhouse heated in winter

If you really want to get serious about growing you have got to add heat to your greenhouse or polytunnel in the colder winter months.

During the colder months in the UK it’s important to protect your plants from unwanted temperature drops which can cause a lot of stress, slowing down growth rates and affecting yields. You really need to make sure that nighttime temperatures don’t drop below 18°C.

The longer you keep your greenhouse warm, the more plants you can grow.

Precious plants such as chillies will not tolerate frost at all. So the idea is to keep the ambient temperature inside the greenhouse or polytunnel above freezing.

In this blog we will discuss 5 essentials you can use to keep your greenhouse heated, so you can choose what works best for you, your budget and climate.

Natural Sunlight

The first and most obvious way to heat a greenhouse is directly by the suns rays. All greenhouses heat up during the day in the sun, and if you have a way to capture that heat and release it later you can continue to keep your greenhouse warm through the colder nights.

The term passive solar greenhouse refers to a specific greenhouse design made to take advantage of this heating source. Often referred to as radiant heat, these greenhouses work but there is often a limit to how much heat these can store and use. They tend to work better in climates with milder winter. In the UK, no amount of passive heat will sustain through the night – you will most certainly have to add heat somehow!

greenhouse sunlight

Electric Greenhouse Heaters

Probably the easiest and most common method of heating a small greenhouse is to use an electric greenhouse heater. Depending on your requirements and how much space you need to heat, this is a simple easy option that doesn’t cost a lot of money to set up.

Ora Greenhouse Fan Heater

If you have a small greenhouse our ORA Fan Heater has everything you need.

This 3KW greenhouse heater is a great little unit that represents amazing value for money. You have several settings to play around: 1000W, 2000W and 3000W, and a dial to adjust output levels.

You can turn off the heater during the day to save costs.

Be sure you have your insulation game right with our Bubble Wrap insulation when using any of our electrical heaters.


ORA Greenhouse Fan Heater

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BioGreen Greenhouse Heater 

This greenhouse heater meets the highest demands of quality and comfort. The body is made out of stainless steel, providing rust free protection.

When standing on the ground all the controls are on the heater. It can be operated from a standing position, eliminating any unnecessary bending for the gardener.

The use of water in a greenhouse is unavoidable and this heater is IPX4 approved for safe use in humid environments. The fan is able to circulate an astonishing 460 cubic meters of heat per hour heating your whole space and preventing any mould formation.

The thermostat can be constantly adjusted to a temperate between 0-36°C with the ability to regulate the precise temperature. This is not only good for your plants but also saves a lot of energy!

Biogreen Electric Greenhouse Heater

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Greenhouse Thermostat

To ensure that your nighttime temperatures in your greenhouse don’t drop below 18°C, we suggest pairing your greenhouse heater up with our Greenhouse Thermostat. This way you can set your outside temperatures and forget about it. Our Thermostat has an accurate temperature control between 0-40°C with its easy to use touch controls.

Greenhouse Thermostat

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Weatherproof Electrical Connection Box

If you want to heat your greenhouse but do not have a source of power, it can be wise to invest in a weatherproof electrical connection box which offers a safe way to house plugs and sockets.

Ideal for plugging in propagators and heaters in a greenhouse, outdoor lights, water features, electric garden appliances, pressure washers, and outdoor heaters.

Weatherproof electrical plug box

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Greenhouse Tube Heaters

Our Greenhouse Tube Heaters are lightweight and require very little power. It makes them ideal for grow rooms and greenhouses to protect from sudden changes in temperatures. They are also useful for propagation where a constant temperature is needed.

These tube heaters are cheap to run and use just £0.005 per hour/ per foot. The 80W and 135W are IP55 rated, resistant to lower pressure water jets from any direction. The 120W & 180W Heaters are IP54 rated, protected from water spray from any direction.

greenhouse tube heaters

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Thermometer & Hygrometer

Use a max-min thermometer to check if your heaters are working well. You could put a digital thermometer sensor in the greenhouse to transmit a reading to the display monitor in your home. Check regularly, especially in cold spells, to ensure the temperature remains above your desired level.

Thermostat & Hygrometer

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Heated Propagator

Invest in a heated propagator to help your seeds germinate. These are great for rooting cuttings and keeping your seedlings warm after germination.

If you only make a few sowings, a windowsill propagator should do the trick, otherwise up your growing game with a rolls Royce of heated propagators a Vitopod Heated Propagator with optional lights.

Our Vitopods’ heating elements are packed tightly together across the base which prevents hot or cold spots, preventing uneven moisture.

They can also be precision thermostat controlled, allowing you to set the temperature accurately to 1°C (between 5-30°C). At a low temperature of 5°C, you can over-winter your plants, providing a gentle bottom heat without stimulating leggy growth.

vitopod heated propagator with lights

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In summary, the above methods of heating your greenhouse we have discussed all work but vary in cost and effectiveness. You need to choose which one is best for you and your circumstances. If you need more help in deciding drop our friendly team a message via our customer support email:

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