A better option is to invest in a heating system.
Diy solar water greenhouse heating systems.
When the controller senses that the sun is shining and your tank needs a warm up it signals the pump to send water through the black collector panels.
Heat sinks are one of the best tools to serve this purpose.
These types of small steps and areas of understanding can make your diy greenhouse even more enjoyable while saving you money and improving.
To use a gas or electric heater can be costly.
Conventionally people do this by blasting energy via heating or cooling systems into the greenhouse.
The primary challenge with greenhouse growing is stabilizing these temperature swings.
There are numerous.
Finally for your passive solar heating system to work you must have a way to store the heat absorbed during the day and release it at night.
Heat sinks use water to trap warmth and release it slowly.
Ideally you should use electric fan heaters which can be easily moved around the greenhouse thus preventing the apparition of cold spots and reducing the risks of plant disease.
The heated water then flows into the storage tank before it s channeled into the heat exchanger.
Passive solar heating such as a 55 gallon drum of water will not work in the dead of winter in maine but it will extend you growing season later into the fall which is most likely what you are after.
Here s how a solar powered water heater works.
Next you must insulate your greenhouse to prevent heat loss.
Closed loop solar heating system.