If you’re feeling cold in these winter months, maybe it’s time to turn the heat up…in your greenhouse! Greenhouse heating will protect your precious plants from becoming ice pops and keep your young plants snug and warm until spring. Heating your greenhouse will open up a whole new world of winter gardening!
But heating a greenhouse can be an expensive luxury, and nobody likes the idea of wasting energy or money. So we’ve put together 5 top tips for keeping your greenhouse warm in the cold months.
1. Insulate with bubble wrap
A layer of bubble wrap clipped to the inside of your greenhouse frame will reduce heat loss and block icy winter draughts. Even an unheated greenhouse will benefit from a layer of bubble wrap. Buy purpose made horticultural bubble wrap insulation from garden centres as this is toughened and UV stabilised. When buying greenhouse bubble wrap remember that larger bubbles will let in more light. You can also use greenhouse bubble insulation to wrap your outdoor pots, protecting rootballs from freezing weather, and preventing your favourite pots from cracking, of course if you have a green house made from certain plastics like Acrylic greenhouse glass from cut my plastic this insulation wont be necessary.
2. Invest in a greenhouse heating system
Electric fan heaters are ideal if you have a mains power supply to your greenhouse. Fan heaters are particularly good for moving the air around the structure which helps to prevent cold spots and reduce the risk of disease. If you don’t have mains power in your greenhouse then a paraffin heater is a better option.
3. Choose the right temperature
Most plants don’t require tropical conditions so don’t waste energy and money on maintaining higher temperatures than your plants require. You can keep your heated greenhouse frost free with a minimum temperature of 2C (36F). Most tender plants such as pelargoniums, half hardy Fuchsias and citrus trees will be happy with a minimum temperature of 7C (45F). This is also a good temperature if you are protecting young plants and plug plants while growing them on. For really delicate species such as Sundaville and other conservatory plants you can increase the temperature to a minimum of 13C (55F).
4. Have the correct thermometer
Invest in a good thermometer with maximum and minimum readings, and check it daily. By keeping an eye on the air temperature you will be able to use your greenhouse heater more efficiently and adjust it when necessary.
5. Position heaters carefully
Electric fan heaters are best sited in an open, central spot at one end of the greenhouse. Always avoid positions where the heater is likely to come into contact with water. If necessary you may need to angle the greenhouse heater slightly to direct the airflow above plants that are stood close by. This will prevent their foliage being desiccated by the flow of warm air.