It’s a winter-time fact in most parts of the country: greenhouses, even those that might be attached to the house or garage, need some kind of heat source (of course, supplying appropriate light is equally important). My first, only partially realized, greenhouse up in the rain forests of Washington’s Olympic Peninsula needed heating just to keep the humidity down. But in most parts of the country, cold is the problem. You may have built your greenhouse with visions of supplying your family fresh, year-’round greens. But winter growth and germination are difficult when soil temperatures seldom climb out of the low 50 degree level. Sure you can use a heating mat to encourage germination. But even the hardiest green grows slowly — very slowly — when nighttime air temperatures plunge.
This video introduces an excellent principle of energy efficiency so it is well worth a look – with the right climate and conditions you could save a lot on your household bills.
If you’re already thinking of installing a new greenhouse on your property, there is now a really good reason to consider attaching it to your house, preferably on the south side if that’s possible. If you have one already (sometimes called a conservatory) all you need to do is to install fans to vent the warm air into your house when the sun is shining.
A greenhouse often generates too much heat, which would normally have to be vented outside so it can easily be moved through your house instead. Frugal Green Girl also explains how venting air from your greenhouse to your house and vice versa will improve the balance of oxygen and carbon dioxide for both you and your plants – she also explains how to use the greenhouse to heat clean air that comes in from outside.
The idea of passive solar heating is well-established. In simple terms, when a house is built with “passive solar design” it uses more, larger windows on the south-facing (sunny) side than on the north-facing side. Some areas are making good use of this idea in new developments but the greenhouse idea takes it a step further.
It would also possible to store the heat from a greenhouse using water tanks and then a heat exchanger to warm the air for night time – this idea would be even more efficient as the heat can be released when it’s needed the most.
There’s a small correction to the “science bit” that she explains: Transpiration is the process by which plants lose water vapour into the air or atmosphere, not linked to removing chemical toxins, but it is true that some houseplants will clean common toxins from the air, this has been studied by Dr. B.C. Wolverton and written up in his book “How to Grow Fresh Air”, with a list of 50 such plants.
One fuel-avoiding, sustainable-friendly method is to build a trench down the center of your greenhouse and, after covering it with palettes or some cobbled walk-way, make compost in it. This might be limited to a small hole in the center of a hobby-sized greenhouse. Even at that, the compost will help moderate temperatures in the greenhouse and you’ll always have a ready supply of garden gold. And the daytime temperatures in the greenhouse should encourage your compost to heat up. Click on our composting guide to learn more.
Now. . . full disclosure . . . we haven’t tried this. Our greenhouse was attached to the south facing side of the house in an attempt to get what little sun we had to give us some solar-generated temperature gain. And it worked, a bit, even on some cloudy days, the concrete grow box and stone walkway serving as heat sinks, giving off warmth to the bathroom and the kitchen porch at night. But an open pile of compost situated (technically) inside the house wasn’t considered to be a good idea.
Another way of creating heat sinks that will absorb energy during the daylight hours and give it up slowly in the cold dark, is to place 55 gallon barrels (or whatever is available and convenient) in corners and other practical locations in the greenhouse. They should be painted black for maximum solar gain. Even buckets of water in a hobby-sized greenhouse, will moderate temperatures just enough to make a degree or two difference, a difference that might be critical. We know a guy who wrapped black garbage bags around packaged tube sand and laid those out in his small house. The bags slowly disappeared as he and his son needed more weight in the back of their pickups.
Electric room heaters are the easiest and probably most popular way to heat a winter greenhouse overnight. Be sure that you follow all safety instructions and makes sure your heater is stable and away from any flammable material. Also take care if you’re running an extension cord out to your greenhouse. Make sure all connections, especially those inside the house, are snug.
Heat circulation is important when using an electric heater. Moving the warm air around will prevent hot spots (and their contrasting cold spots) as well in reducing condensation that heating will encourage. Some heaters have built-in fans, some need additional circulation.
We’ve been surprised at the number of greenhouse operators using wood heat to warm their buildings. With propane becoming more and more expensive, wood and pellet stoves, again with provided circulation, are operating effectively and more cheaply than other fuels. Large, commercial-sized greenhouses are finding wood a viable alternative to expensive gas and petroleum products. When installing a wood stove in the green house be sure to follow all your local code requirements. Stand alone pellet stoves are especially easy to load and operate and most come with some kind of temperature control. Some have blowers to circulate heat.
I don’t think I would put a wood stove in a plastic covered greenhouse. Stovepipes can get very hot and the risk of melting or igniting Visqueen and other plastic covers seems great short a stove vented out through a masonry foundation or some other such careful planning. I had hoped to put a small, slow-burning wood stove in my attached glass greenhouse, both to heat the growing things and the rooms on that side of the house; one of the unrealized dreams in my green house.
Most People Don’t Have The Guts To Try This:
An amazing discovery in an abandoned house in Austin, Texas: A lost book of amazing survival knowledge, believed to have been long vanished to history, has been found in a dusty drawer in the house which belonged to a guy named Claude Davis.
Remember… back in those days, there was no electricity… no refrigerators… no law enforcement… and certainly no grocery store or supermarkets… Some of these exceptional skills are hundreds of years of old and they were learned the hard way by the early pioneers.
We’ve lost to history so much survival knowledge that we’ve become clueless compared to what our great grandfathers did or built on a daily basis to sustain their families.
Neighbors said that for the last couple of years Claude has tried to unearth and learn the forgotten ways of our great-grandparents and claimed to have found a secret of gargantuan proportions. A secret that he is about to reveal together with 3 old teachings that will change everything you think you know about preparedness:
Old Time Wisdom ( Timeless Bits of Wisdom on How to Grow Everything Organically, from the Good Old Days When Everyone Did you can prepare yourself for war by moving to the countryside and building a farm, but you must take guns with you, as the hordes of starving will be roaming. Also, even though the elite will have their safe havens and specialist shelters, they must be just as careful during the war as the ordinary civilians, because their shelters can still be compromised.”)
The Lost Ways (Learn the long forgotten secrets that helped our forefathers survive famines,wars,economic crisis and anything else life threw at them)
LOST WAYS 2 ( Word of the day: Prepare! And do it the old fashion way, like our fore-fathers did it and succeed long before us, because what lies ahead of us will require all the help we can get. Watch this video and learn the 3 skills that ensured our ancestors survival in hard times of famine and war.)