Heating My Greenhouse

During the winter you don’t just have to think about heating your house. If you have a greenhouse, these also need to be kept warm, in order to protect your plants. With the right heating source in place, you’ll be able to enjoy gardening whatever the weather and have plenty of healthy plants.

To help you decide on the most effective and cost efficient way of heating a greenhouse, here are our top tips.

Bubble wrap insulation

A simple way to keep the heat in your greenhouse is to attach bubble wrap on the inside, to insulate the space. Specialist horticultural bubble wrap is the best option, as it is UV stabilised and toughened, and you’ll let more light in with bigger bubbles.

Fit a heating system

If there is a power supply in your greenhouse, then electric fan heaters can be a useful way of providing additional warmth. These types of heaters, such as the Palma Greenhouse Heater or an 8×10 greenhouse heater, circulate the air within the space, to reduce the likelihood of cold spots.

Set the best temperature

You can save energy and money by using the thermostat, so the heater only switches on when it drops to a certain temperature. It’s also important to decide on the right temperature for your greenhouse, as you’ll be wasting money if you have it higher than the plants actually need.

Place heaters in the right positions

If you’re using an electric fan heater, these are best placed at one side in an area that is open, which enables the heat to circulate effectively. When there are plants close by, you should angle it slightly to allow the warm air to flow above them.

Don’t heat the whole greenhouse

It’s not cost efficient to heat the whole of your greenhouses space when there are just a few plants that need protecting. Position all your delicate plants in one area and concentrate the heat here. If space is limited, you could invest in a slimline heater, which is a low energy appliance and offers a constant heat.

Propagation heaters

To keep seedlings warm and help them to germinate, you can use a heated propagation system, such as a windowsill propagator or heated propagation mats.

Horticultural fleeces

When there is a particularly cold night, horticultural fleeces will keep your plants warmer without having to turn the heater up. You’ll need to remember to take this off in the morning to allow the plants to get the right amount of ventilation and light.

The importance of ventilation

Increasing the heat within a greenhouse can result in extra humidity, so it is essential to have good ventilation to reduce the problem of fungal diseases. Ways of reducing the amount of moisture include watering plants only when necessary and opening greenhouse vents on warm sunny mornings to clear any condensation.