Tried to place this photo on my previous post. Didn’t work, so here is my
greenhouse that was referenced.
I’ve been away for a while but now I’m back.
Cooler weather has arrived. Time to complete many garden chores in preparation for winter. The first important task is to get the greenhouse in order. My greenhouse is 10’X12′; plastic waffle panels; four ceiling vents, purchased unassembled from Harbor Freight. My husband, brother-in-law and I took two days to assemble and install the house. It has been up four years and I have been extremely satisfied.
Over the years a few adjustments have been made in the greenhouse to combat the cold winter weather in our area. Until the outside temperature reaches 25 degrees or under I heat the greenhouse with a small electric milk house heater working at medium, which keeps the temperature at 40-50 degrees. Outside temperatures of 25 degrees and under I use a kerosene heater. It will run 12 hours on one gallon of kerosene. Usually, once the sun comes out the supplemental heat is turned off. A very small fan, at roof line, runs continuously to circulate the air. Using these heaters, and with the adjustments listed below, heating the greenhouse over the winter has been very inexpensive.
In researching kerosene heaters several references stated they should not be used in a greenhouse. If the house is air tight, I suppose this is good advice, however, mine is not. I allow outside air to come in through a small adjustment in two ceiling vents. Two out of the three past winters the kerosene heater was used with no ill effects to humans or plants. The third winter was mild and the kerosene heater was not needed. The kerosene heater should be in good working order, otherwise soot has a tendency to cover the plastic wall panels.
Originally no floor was installed. As the ground around the greenhouse froze it became very difficult to keep the inside temperature at 40-50 degrees. The second year a floor was installed consisting of landscape timbers laid crossways; the spaces filled with straw; and then the wood floor. That alone increased the inside temperature by 5-7 degrees.
The roof peak on the greenhouse is 10′. A good portion of the heat goes to the ceiling. To combat that issue, in addition to the fan, plastic sheeting was installed over the inside roof panels, except those with vents. Light is still available to the plants but heat cannot escape and is circulated throughout the greenhouse. The back of the house is to the north; the left side faces west. Forest is around both back and west side, preventing sun shine reaching inside the greenhouse in those areas. Both remain colder in the winter. Plastic sheeting was installed on those wall panels. The sheeting can be raised or lowered as needed. The use of the plastic sheeting raised the temperature another 7-8 degrees.
I spent the last two days removing all roof panels, cleaning the aluminum framework; scrubbing the panels; and replacing each one with additional clips. Originally we only placed three clips on each side of the roof panels which allowed cold air to seep in. I now have six clips on each side which will decrease the flow of outside air to practically nil. It was necessary to replace one of the roof panels. Last winter’s snow caused the panel to cave in. This was not a defect in the plastic. It was my fault for not scraping the snow off the roof in a timely manner.
My husband, bless his heart, has now installed four automatic pneumatic openers/closers in the ceiling vents. The last three winters I have had to climb a ladder each time a vent was to be opened or closed. The automatic opener/closers are a blessing!
Next, new plastic will be installed on the cleaned roof panels and replaced where needed on the wall panels.
Then, the floor will be swept; tables put into place; pots and soil to be used over the winter put in place; the greenhouse closed and fumigated.
While the greenhouse is fumigated all plants to be wintered over will be identified and sprayed with Capt. Jack’s Dead Bug organic insecticide, readying the plants for the winter. Following the procedure of fumigating the greenhouse, pots and soil plus spraying the plants before placing in the greenhouse, I have never had a pest problem over the winter.
I hope the above information has been helpful to those who have, or are considering, a greenhouse. If a greenhouse is being considered I strongly recommend the Harbor Freight house. Comes in three sizes, mine is the largest. Often can be found on sale. They are a challenge to construct but by following instructions exactly it can be done without too much difficulty.