greenhouse design.. temperature - Orchid Board

silken · #7 01-15-2015, 10:33 AM

We have what I guess you can call a greenhouse attached to our home. It is heated right thru our winters which are as cold or colder than most people here on Orchid Board will ever see. It is not uncommon to have a week or more at a time of -36C or colder and we have fairly long winters. We didn't have a choice of choosing which way to orient it since we attached the long 30 ft. wall to our home. So the wide part faces west and the short end of windows faces south. It is 11 ft. deep and one short end attaches to a heated garage. Our landscaping made it possible to dig it into the ground 3 ft. We poured a heavy concrete pony wall with good foam insulation in it. The windows are triple glazed and able to open in the summer. The roof is triple glazed poly carbon panels. The frame is aluminum with foam insulation in the hollow parts. We have an energy efficient NG furnace in there that heats the greenhouse and 1/3 of our home. I am sure our gas bills are higher than if we didn't have the greenhouse. But the house wall it is attached to is all window anyways, so we don't feel that the bills are outrageous for what we have. Natural gas here is more affordable than some parts of the country. We do have to run a dehumidifier in winter and I usually don't have as much humidity as I would like. In very cold temps, it will collect on the windows and run down and just make a mess on the ledges and cause mold if it is sitting wet for too long. But it is around 40 to 45% in winter and I keep it cooler at 65F in the day and 55F at night. So extra humidity might not be real good anyways. I have been using this greenhouse or it's predecessor that had a fir wood frame for about 25 or 30 years. Not always for growing orchids, but for keeping tropical plants and growing many bedding plants.

We get the other extreme in summer of hot and sunny. We use a shade cloth in spring and on the short southern end there is a large exhaust fan that cuts in when the temp reaches 90F. We have 3 hanging ceiling fans that run 7/24 year round. and an intake fan for summer that runs when the exhaust fan runs. I often open windows in summer also. We have a misting line that runs the length of the ceiling that comes on several times a day in summer.

So that is a rough Idea of what I do to grow my orchids in a fairly harsh climate that sees both extremes in summer and winter. I do supplement lighting with T5's in winter since days are short and there is usually snow on the roof, which probably acts as a good insulator.

With some imagination and some research, anyone can build a greenhouse and make it work. It's just a little easier for those in a climate more friendly to the idea

By the way, I grow Catts, Oncidiums, Phrags, Paphs, Dendrobiums with a reasonable amount of success. I need to create small microclimates with heating mats for some tender ones in winter, and find the cooler shady spots for others in the summer.