How to Heat a Greenhouse in Winter

A four-season greenhouse will provide you with fresh food year-round. Regardless of what region you live in, it’s possible to have fresh vegetables growing in the middle of winter, all you need is a consistent heat source.

Use these tips and tricks to transform your existing greenhouse into a productive food factory year around.

Off-Grid Heating

Most gardeners who would be interested in a four-season greenhouse would also want to have a sustainable source of heat instead of being dependent upon fossil fuel, wood, or electricity. There are several ways to increase the temperature inside a greenhouse without the use of purchased fuel. You won’t even need solar panels to provide enough heat to grow vegetables in the winter with these ideas.

Compost Pit

Create a compost pit in the center of your greenhouse to create a sustainable heat source for growing plants.

Depending upon the size of the greenhouse, the compost pit could be a hole or trench centrally located and covered with recycled wooden pallets. Small, hobby greenhouse could use a five-gallon bucket for composting organic matter.

As the compost decomposes it creates enough heat to warm the interior air to promote plant growth. As an added bonus, you will always have a ready supply of nutrient-rich compost.

Heat Sinks

Black buckets or barrels filled with water and placed in the corners of the greenhouse will absorb heat during the day and release it at night. The black plastic will warm the water in the buckets or barrels, giving off a little steam to warm the air.

The warmed water will increase the humidity level inside the greenhouse, which the plants will love, and you will always have readily available water for use during gardening chores.

Southern Exposure

A winter greenhouse needs a southern exposure so it can utilize all the available heat and light the sun has to offer in the winter.

Clear plastic roofing and side walls will allow much-needed sunlight to penetrate through into the greenhouse to warm the air and promote plant growth.

Bubble Wrap Insulation

Bubble wrap plastic is a great insulator and works well when placed under or between the layers of plastic sheeting used for a greenhouse. The air bubbles help preserve the warm air and the clear plastic allows the sun to shine through.