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Greenhouse Doesn't Heat Like Expected

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Postby MareE » May 15, 2008 9:05 am

Aaaah, the convection theory, Savona. Good thinking. Your greenhouse is always exploding with excellent plants awaiting...well...planting.

Informative thread!

Mare who dreams of greenhousing some day;o}
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Postby Sheikea » May 15, 2008 9:39 am

Don't forget black holds heat.That might help if you have a black floor.?
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Postby packrat79 » May 15, 2008 10:18 am

Last night I had much better luck keeping the greenhouse warm, I was able to keep it above 50 despite near-freezing temps outside. I think the main reason was because the wind finally died down. Also, by last night I had covered roughly half of the interior with a second layer of plastic (leaving a gap between the two layers). The second layer of plastic also means the heater has a smaller area to heat now, which might help.
As for plant growth, my plants are already late-sown and many are clearly not going to be ready to sell by the end of the month. I'm not sure if I should sell them as-is or wait until later. I'll make another post on that subject some other time.
Thanks for the advice.
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Postby MareE » May 15, 2008 11:13 am

Hey, Packrat, there was someone here who devised heating of greenhouse from something out of nothing ingeniuosly. Noted it mentally (bad mistake) and sooner or later it will kick in HOW her invention paid off. As usual, the application was butt-kickingly simple like why didn't I think of that myself? sorta deal.

MareE still thinking.. I mean remembering;o}
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Postby Eeyore » May 15, 2008 11:31 am

Well, you are certainly learning by trial and error Pack. And doing admirably well. Personally I wouldn't have had a clue about building or heating a greenhouse.

Water holds heat very well so if you've got room for some large barrels that would heat well in the daytime, place those about the greenhouse and fill them with warm water.

Another trick is to lightly mist your plants if it is going to drop down to cool temps. It protects the plants from freezing.
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“Those who say it can't be done are usually interrupted by others doing it.” ` James Arthur Baldwin"
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Postby green thumb guy » May 15, 2008 11:50 am


Not sure how long you have beenn dabbling in plant selling.

I've played around for several years now. If you are looking at annuals, then i would be starting theminside and then move the flats out top the greenhouse fro growing. I foiund it to be a tricky thing with trying to produce decent plants at a reasonable time for selling.

I no longer wanted to try and compete with everyone else who buys flats of plants and blows them out. I put too much tie and effort into them.

To be honest, people who come to buy them seem to have no concept of the effort and resources required to be put into them.

Instead, I switched to perennials and would spend a whole season growing them with sales the following season. I liked the quality of the plant.

I do grow some annuals like cannas.

I also listen to what people request or would like to seeat our sale.

Trial and error has been the school I'm enrolled in. I found this spring to be very difficult. when we had the high temps of 20 C's for a week or more, I had several hostas leaf out and had a hard time protecting them from the frost.. Despite all my efforts, I see some damaged leaves - though it won't harm the plant - it's not the look I want.

I would love to talk to you more about your plant sale but I have to run as I'm prepapring for ours this weekend.

Feel free to PM me and we can talk.

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Postby dlb » May 15, 2008 12:45 pm

There was someone in my local group who set up a greenhouse draping plastic over the swing set, sealing the plastic edges and putting a small heater inside. She has graduated to a real greenhouse this year, but her improvised one worked well for her last year.
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