Well, this was a new one for me. I assumed that when you build a greenhouse, that you put windows on the south side, maybe a glass (polycarbonate roof) and WaLa! It warms when the sun hits it and you will have lovely veggies all winter. HA!
I should have known it wasn’t that simple. I spent most of our sunny fall going back and forth to the greenhouse to open or close windows. If the sun was out, the temperature inside could top my thermometer at 120 degrees in just thirty minutes. So, I would open windows, but with the ambient temperature in the forties, I would have to regularly check the temperature to make sure it wasn’t cooling off too much. As the nights cooled into the thirties, I ran a couple extension cords out to the greenhouse so I could run a heater at night. That worked until we got the electricity installed and I could use a temperature regulated heater that turns itself off at the desired temperature. To solve my sunlight problem, friends said I needed vents.
I bought the recommended automatic, temperature regulated vent openers, and had our handyman ready to create vents and cut into the roof, when we noticed they were not recommended to use in winter. Sigh. Another friend recommended a solar RV vent. Hmm. I ordered one, climbed the ladder, cut the hole, installed the vent, and WaLa! It worked as advertised. When the sun hit the panel, the fan ran and pulled hot air out of the greenhouse. Only, it wasn’t pulling enough air out to keep it ventilated and cool. And, to add injury to insult, because there was no damper, it was allowing any remaining warm air to escape at night! Not good.
It was time for some more research. Somewhere on the vast resource called the internet, I came across an article talking about the need to insulate a greenhouse. A novel idea I hadn’t thunk of yet. Off to the local home improvement store I drove to pile several sheets of 2” thick foam type board into my van. Two days later they were successfully installed on the wooded north wall and joined with metal tape. That seemed to help a bit, and now I have a shiny silver wall. But, the temperature was still soaring in the sunlight.
More research indicated that I might need to insulate the polycarbonate that I used for the south walls and south facing roof. I had already covered my vent hole, so as to stop that air exchange. But, bubble wrap on the poly walls/roof? There were several greenhouse suppliers online I could buy “horticultural grade) bubble wrap from for $300, if I was willing to pay another $350 for shipping! Not on your life! Time to see how much non-horticultural bubble wrap cost. I was able to find a somewhat local packaging supplier in the area and to purchase the amount I needed ended up costing me $150 plus an hour of driving time and gas. Not bad actually.
My father helped me with the installation of it. After several unsuccessful (and painful) attempts to use a hammer stapler to install it, my father suggested I go back to the shop and get an electric stapler and extension cord. I resisted. After noticing a huge bruise that had developed at the base of a finger, I relented and did as he suggested. That was so much easier! While we worked, I apologized for being so stubborn and not listening to him. Will I ever learn? I hope so.
Yesterday was our first sunny day since insulation was mostly completed (I still have to tape my seams and edges). It rose to a reasonable 80 degrees, with no window opening required. I know that I will eventually need to get a temperature controlled vent system in my cute little greenhouse. And I still have to figure out how much water my plants need indoors, but, this works for now. Maybe, just maybe, I am getting this thing figured out.
I hope that you are able to find the answers you are looking for today to solve whatever problems you are dealing with in this life.