In these days of high priced heating options for greenhouses, more and more people are learning about alternatives to propane and electric heaters. Solar energy can have a short return on investment for greenhouse heating. Yes, a sunny February day may have your growing space warm during the day, but after the sun is down- you may have to worry about extreme temperature fluctuations affecting the health of your plants. Storing heat from the sun during the day and then allowing it to keep your greenhouse warm during cold nights is an excellent way to make your growing operation even more sustainable. The picture in this post was taken at Tricycle Gardens in Richmond, VA and shows the commissioning of the solar thermal heating panel that we donated and installed for this non-profit organization. A loop of plastic piping was installed in the gravel floor of this greenhouse and this solar thermal panel pumps hot water through these pipes to warm the gravel in the greenhouse. The gravel holds this heat during the day and gives it back at night, helping the growing space maintain an appropriate temperature for seed starting. Notice the solar photovoltaic(PV) panel mounted on top of the larger solar thermal panel. This greenhouse heating system requires no fossil fuel inputs because this little PV panel provided the needed electricity to operate the pump that pumps the water from the solar thermal panel into the greenhouse underfloor piping. When most people think of mainstream solar concepts, images of long arrays of shiny rooftop panels come to mind. Well, there are simpler and more affordable solar strategies with short ROI’s that can be utilized at your home greenhouse or commercial growing operation. And as always, STI is here to offer you training and consultation in these areas. This summer we will be holding reasonably priced Saturday workshops that address solar thermal greenhouse heating, as well as other various topics of interest in relation to sustainable farming. Also, before the end of the growing season, we will hold a weekend workshop where participants can build their own solar dehydrator. Keep your eye on our class schedule and we hope to see you soon!