Getting the greenhouse ready

Cold climate heating ideas–

Almost ten years ago already, we dropped some serious cash on a polycarbonate walled greenhouse. This was a dream come true for me, we had saved for several years to buy this thing. Of course, it had to be during a blinding snow storm in March when it was delivered. The truck driver backed down our long driveway and we all helped in the unloading of my new Jan cave. It was a build it yourself project, with everything needed to put it together, including the nuts and bolts. That year it sat at the end of the driveway until the second week in May before we could get started putting it together. We had 4 dump truck loads of gravel dumped where the greenhouse was going to stand. We had to move that humongous pile by rake and by wheelbarrow. Let me tell you this! Hubby very rarely uses bad language, but during the actual building,he said lots of them.

After a year or two of growing in my new greenhouse it became clear we needed added heat in early spring. Our climate is too unstable, we needed added heat if we were going to start tender seedlings. I did some research in off grid greenhouse heating systems (this was long before I discovered rocket mass stoves ) and I discovered a book called Solviva How to Grow $500,000 on One Acre & Peace on Earth written by Anna Edey. She put together a beautiful book About how we can provide electricity, heating, transportation, food, solid waste and waste water management in ways that reduce pollution and depletion of resources by 80 percent or more, and that at the same time reduce cost of living and improve quality of life.Revealing the truth. I simply love this book, it is just full of beneficial ideas for the human condition.

Anyway, I stole her idea of a wood fired greenhouse heating system and modified it to fit my small 16′ X 20′ greenhouse. The following is how we did it.

Start by cutting a 55 gallon steel barrel in half, or there ’bouts. Dig a hole in your greenhouse slightly larger than the half barrel.  Our greenhouse is on the south side of a hill. At spring thaw melting snow runs down the hill which floods the floor. Two years in a row it was deep enough that it made it’s way into the center of the greenhouse and into the stove putting out the fire. We have since learned and leave about 3 inches sticking up out of the ground.

Now put the half barrel into the hole you just dug and back fill, tramp down the dirt. Next you’ll need to add the pieces of angle iron to give the heavy sheet metal some support. The added angle iron will help if you should put a smaller barrel of water on the sheet metal to produce humidity. Put on the gasket. Use stove gasket glue to hold the gasket in place.
Measure the barrel length and width, cut your sheet metal a good inch or so larger than the barrel measurement. Add a hole for the 6 inch chimney to sit in and cut the sheet metal about two thirds the way down to make for a loading door. Weld study hinges to the two pieces. When that is complete carefully lay it on top of the barrel patiently waiting in the hole. Put in your chimney and start your fire. I added builders blocks to stabilize the chimney and to add a heat absorbing mass. Pour water on the cold bricks to add humidity to the area when you fire up your stove.

All this seems like a lot of work but it is well worth the effort. The fire in the this woodstove heats the ground in the greenhouse providing a type of radiant heat. I can set my seeds flats on the floor of the greenhouse and in just a few days have little green shoots sticking up out the soil. This stove has served us well now for many years.

Let me know your thoughts.


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