Heated Greenhouse in a Cooler Clime

Discussion in 'Gardening & Plant Propagation' started by WindowOrMirror, Dec 19, 2005.

  1. WindowOrMirror

    WindowOrMirror ..where do YOU look? Supporter

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    We live in Zone 4(a) (NorthCentral WI). I am wondering how long it is practicable to extend the growing season with a smallish greenhouse? What if one was willing to heat it? Perhaps a greenhouse within a greenhouse for air insulation?

    R
     
  2. BrahmaMama

    BrahmaMama Well-Known Member

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    I've been thinking about the same things too. A smaller plastic greenhouse inside a slightly larger one is probably a good idea.
    In this area, I would hope to be able to grow until mid Dec. and then start again in mid Feb. when the first warm spell hits (give or take considering the weather.)
    Keep in mind, smaller is probably better, heating costs wise.
    What were you planning on using, I was thinking Kerosene space heater.
     

  3. Bresias

    Bresias Restless User

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    Some guy in Bonners Ferry (far north Idaho) kept tomatoes going until the first week of December in a greenhouse he actually dug into the ground. North wall, an earth berm, dug down six feet for the 'walkway', and the beds themselves looked to be about four feet down. I might not be remembering rightly, but he used sliding glass doors for the south side. Our ground freezes several inches down, and he is definitely in a zone 4 situation.

    I'm considering this, as our growing season is only 70 days between frosts.

    I saw this in Mother Earth News (between all the ads). Sorry, can't remember the issue.
     
  4. BrahmaMama

    BrahmaMama Well-Known Member

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    That's brilliant !!!! :happy:
    I have been collecting old double panes windows because I'd much prefer a glass house (wind)..
    I could easily "create" something like that!
    Thanks for the input! :D
     
  5. pickapeppa

    pickapeppa Well-Known Member

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    Hi red-eyed devil. We are in zone 5a, just south of you about 3-4 hours. Ours is a 16 x 16. You can grow cooler season vegies throughout the winter for the most part. Things won't grow, but will stay harvestable all winter. In the hoophouse, it gets colder and freezes harder than in the greenhouse. So, in the hoophouse, our celery froze solid in mid-January and was lost, but usable up to that point.

    You won't be growing your typical warm-season produce in the winter, but if you are just interested in extending the season for them, I would say you could safely add 2 weeks to a month at each end of the season.

    Right now, we still have cilantro, spinach, radishes, parsley and green onions in good shape in the greenhouse.

    Our hoophouse collapsed in some big winds in early November, so everything froze when the temp dropped into the teens that night. However, the carrots that were growing in there will be usable until they start growing again in the spring. In another 6 weeks I will probably start planting greens in there again. Happy, happy! :D

    Have you read Eliot Coleman's book yet? If not, it's called "The Four Season Harvest". If you go the route of a double layer of protection, you can get more to last longer.

    One spring (Februaryish) we used transparent sheet plastic to wall off the inner center of the greenhouse floor to ceiling. In the new 'room' we had two shelving units at each end of the room. In the middle we placed an oil-filled heater on stone and ran an extension cord (mistake, btw). We started seeds in there in mid-February successfully, yes, even the warm-season varieties! We kept the heater on the low setting at night unless a brutal cold was forcasted. Oftentimes the high setting was too much. I had to get out there first thing in the morning to shut it off or it would reach 90F+.

    Well, that's our limited experience in a pumpkinshell. We've been at this about four years and haven't got our system settled yet. But every year, it gets tweaked and we get a little closer to the ideal we are looking for. Hope it helps.
     
  6. wy_white_wolf

    wy_white_wolf Just howling at the moon

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  7. rzrubek

    rzrubek Flying Z

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    My two cents worth says to build as large as you possibly can, or build in such a manner as to be easily added on to later. Also, remember that compost heaps create heat so make room for a couple of those in the greenhouse. If you google "Pit greenhouse" you will find more info on the type of greenhouse they are talking about.