Greenhouse Heating Solutions, Which is most cost effective?
There are a number of ways to heat your greenhouse using low- or no-cost solutions. Before you invest in a heating solution for your greenhouse, first determine if you need heat at all. If you live in a temperate zone and you use an insulating greenhouse plastic, you may not need to heat your greenhouse.
SolaWrap™ is a relatively new option for greenhouse plastic covering materials, in the US. However, this greenhouse film has been used for over 30 years in Europe, with more than impressive results. It has a higher insulation value than double wall polycarbonate greenhouse film.
SolaWrap™ looks like bubble wrap, however it is highly durable with 17-mil thickness of food grade polyethylene, which encloses the air bubbles. This uniquely engineered air bubble design serves two main functions. They insulate, since air is the most insulating substance and they diffuse light. This diffused light helps your plants grow faster, since the light is reaching all parts of the plant instead of just the top of the leaves.
In the Mediterranean, growers are reporting a three-week advancement in their tomato crop under SolaWrap™, as compared to other greenhouse coverings. SolaWrap™ also affords a longer lifespan. No SolaWrap™ greenhouse has ever needed to be recovered in Europe, in 30 years!
After you cover your greenhouse with this specially engineered, insulating, greenhouse plastic, then you can assess whether you need heating.
Implementing other no-cost solutions to heat your greenhouse would include filling your greenhouse with elements with thermal mass. Thermal mass can hold enough heat to possibly stabilize the temperature inside your greenhouse, depending on your greenhouse size and how much mass you have. Rocks will hold a lot of heat, as will soil and water.
Building your grow beds high enough to fill with a layer of rock and growing soil will help to trap the sun’s heat without adding any extra mass. Your water tanks will also hold a lot of heat. Cover the north wall of your greenhouse with a reflective material and place an open water tank beneath the reflective material. The reflection will funnel the sun’s heat into the water. The water will absorb the heat. When the sun sets and the temperature drops outside, the water will release the stored heat, creating a passive solar heating system.
If your greenhouse requires more heat than a passive solar mass system combined with elements that work as thermal mass can provide, two low-cost solutions are an electric space heater or a rocket mass heater.
An electric space heater is the simplest solution. Set up an automated system for your space heater so it will click on automatically when the temperature drops below a certain threshold, ensuring your plants will never be exposed to the cold. This requires no effort from you, as it is automatic. If you heat your greenhouse with a space heater, your greenhouse will be dependent on your source of power. In the event of a power loss, your plants could be in peril.
A rocket mass heater is an amazing paradigm shift in wood stove heating. Rocket mass heaters burn the fire sideways and use trapped convection to absorb that heat into a thermal battery, which resembles a tunnel. The battery then releases the heat over a period of 24-48 hours. The best part is, the thermal battery can take the form of a bench, giving you a greenhouse seat warmer! Or you could place the thermal battery under a grow bed, and grow warm season plants in the winter.
Your choices should reflect your situation: your climate zone, your budget, lifestyle, the size of your greenhouse, and the greenhouse covering you select.
If you are in a location that will require a heat source and feel a bit overwhelmed by it all, give us a call 1-781-816-7811 or firstname.lastname@example.org, and we can help you sort it out.