6 Effective Heat Retention Hacks to Keep Your Greenhouse Warm in Winter

When saving money and cranking up the heating systems don’t go hand in hand, the next best thing is to find hacks to retain heat in your greenhouse and save money!

Whether you're growing tropical plants, sowing seeds before the growing season, creating a warm haven for yourself, or simply preserving the heat inside your greenhouse, it’s important to ensure it does its job without breaking the bank. Here are seven of the most effective ways to retain heat and reduce heat loss, so you can enjoy a warm greenhouse year-round.

 

1. Good Insulation

Not much of a hack, but more of a prevention step before diving into the hacks: ensuring your greenhouse has proper insulation is key to minimizing heat loss. Consider using double-layered plastic film or plastic sheeting on your greenhouse walls and roof to significantly improve heat retention. The right temperature is crucial for plant health, and well-insulated greenhouses are designed to trap heat and maintain the optimal temperature without relying on expensive heating sources.

2. Use Thermal Mass for Long-Lasting Heat

One of the best ways to retain heat in your greenhouse is by incorporating thermal mass—materials that absorb heat during the day and release it at night. Water barrels or large containers filled with water and even big rocks can act as a natural heat sink, absorbing the sun’s heat during sunny days and slowly releasing it when the temperature drops. These thermal energy sources create a warm greenhouse that can prevent heat loss on cold nights and during colder climates.

3. Use a Greenhouse Heating System

For large greenhouses or those in colder climates, installing a greenhouse heating system can be an effective way to maintain warm temperatures. The best systems allow you to manage the temperature remotely, so you can easily track heat levels. Options include electric greenhouse heaters, propane heaters, or even a wood stove, and for a more energy-efficient solution, solar panels. While this is an investment, it makes sense to splurge on it, as it extends the life of your plants and keeps your greenhouse temperature consistent without the constant worry.

4. Add Layers of Insulation

In addition to standard insulation, greenhouses can benefit from added layers like row covers, horticultural fleece, horticultural bubble wrap, and thermal curtains. These materials provide an extra layer of protection, trapping heat around your plants and reducing heat loss, helping to maintain a warm environment. This approach is especially effective on cold nights when temperatures can drop unexpectedly.

5. Harness the Power of the Sun’s Heat

Positioning your greenhouse walls and roof to capture direct sunlight is essential for maximizing sunlight exposure while minimizing energy used for heating. The north wall, especially in the northern hemisphere, should be insulated with extra insulation or reflective materials to retain heat during the day, as sunlight can be limited during the winter months. By focusing on solar energy, you reduce reliance on artificial heat sources, helping to keep energy costs down while providing your plants with a steady, natural source of warmth.

6. Move Your Compost Pile Indoors

If you have a compost pile outdoors, consider moving it into your greenhouse to take advantage of the heat it generates. As organic material breaks down, it produces heat—known as a "heat sink"—which can help maintain a warm temperature in your greenhouse. This natural heating process not only contributes to heat retention but also provides the added benefit of readily available compost for enriching your soil. It’s a simple yet effective way to keep your plants warm during the colder months.

Final Thoughts

Maintaining a warm greenhouse during the colder months doesn't have to be expensive or complicated. The key is to use unconventional methods to your advantage. Techniques like utilizing thermal mass, installing good insulation, moving your compost pile indoors, choosing the right location, or creating your own heat source are all effective ways to reduce heat loss.