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Hi fellow Rocky Mountain gardeners. This summer's garden is history, even with the somewhat mild days ending this October. The veggie garden did pretty well this year thanks to more rain that the last two years, even with some garden negligence because of building projects on the homestead. The point of this post is my next building project which is slated for next spring. It's the greenhouse. I'm from the gulf coast (New Orleans) originally, and want to extend the growing season, plus include perennial plants I miss from the south. I'm torn between a few greenhouse ideas. I like the low cost of the asymmetrical gable style structures, but want something wider than 12-14 feet by whatever length. I have 20 feet of recycled double insulated glass casement windows (five- four feet wide by five feet high) that might work for that type of structure, plus some clear twin wall rigid poly (saved from the dumpster) for more solar gain surface. That sounds great, but I'm also interested in the "grow domes" that are made over in Pagosa Springs. I stumbled across one in Jaroso, CO last week, and met the owner out in front of his house who invited me (and my wife) to take a look. It was great! The one they have is a 26 foot dome, and they get veggies and fruit all year using minimal supplemental heat. They shared sweet strawberries, tomatoes, and have squash, peppers, chard, herbs, and even figs and lemons growing in there. I guess because my garden finished in September, and my longing for a 'Celeste' fig and citrus (and bananas!), I wanted to place an order for a dome that evening. But I waited, since I've been playing around with other designs. I've been designing a greenhouse with elements of the domes, but with my personal preferences included. I was thinking about a hex or octagonal design to get more sun throughout winter days, but include the water tank (heat sink), and more insulation on the north side than a dome provides. I can still use the insulated glass windows I already have, along with the poly. The point of my post is to ask any of you what greenhouse design you use up here where winter lows get below negative 20 or 30, and to ask what success you have with it. Thanks in advance, Steve
Sorry you didn't get a reply sooner - I don't know what everyone else is doing, but I have been working extra hours.
Colorado is a natural for "Solar". Our thin dry air makes for a lot of sunlight. For most outdoor plants to receive "full sun", you need just 6 hours here. Things to consider - heat sink - you mentioned this, so you have thought about it. The more water the better for stabilizing temperatures. I agree that insulating the north wall is a good idea - winter is a long season and you don't need the extra light in the summer months. You might want to make the north wall another heat sink. It is easy to get too much sunlight here - ventilation to get rid of excess heat is essential. It is easy to fry things here on sunny days. Since you are considering a larger greenhouse, I'd consider trying some sort of partition/zoning. Then you could grow cool-season annuals and warm-season tropicals, and not have to keep the whole thing heated.
PS - I forgot to mention you are going to need supplemental LIGHT for some things that are day-length sensitive. Last winter was my first with a lemon tree. I found that even if it was kept warm enough, it needed 12 hours minimum light, and it wasn't getting it - so it wanted to lose its leaves in the fall, and then didn't bloom well in the spring. It is doing better this winter under lights even though it is a cooler location. The brassica/crucifer family sulks in the dark, too, but perks up well in the spring.
Steve, your message slipped by me, too. I will try to get a video done soon, to include more pictures of my "tunnel on top of cement block piers" greenhouse. Over here, we've been down to -1 degree so far, but there's worse to come, I'm sure. I had some tomatoes and squash near the GH opening wall and they got a little frost. I took off the frosted leaves and they're doing okay - they were the ones that got frost outside, that I repotted and moved into the GH. They were probably whispering, "Promises, promises..." lol :) The avocado trees are putting on new growth now, after the biggest was transplanted into a bigger pot. There's a fan and two small heaters out there. The electric bill went down this last cycle, so will await the next one to see if there's a jump.