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Phoenix, AZ

I am building a greenhouse of some 6 X 7 dimensions and will have a little heater for it.

Here is my concern: I cannot be around every day to open the flap to keep it from overheating. Already tests done in a smaller one show 110 F plus easy without venting. Remember we are in Phoenix. No idea but maybe a larger greenhouse won't accumulate heat so quickly?

Should I just partially vent the greenhouse continually? Our lows will get down to high 30's and I want to keep my greenhouse above 55 F at all times. This is easy but its keeping it from overheating is the problem. We see 70's sometimes this time of year.

What should I do?

1/5/2006 9:46:29 PM

San Diego, Ca.

Wow Ben, Going with a green house! Can't wait to see some pictures of what you're up to. I was just out there in Phoenix last week...I should have got in touch with ya.

I think, if I remember right, Tremor has some experience in automated flap doors that work according to temperature.

Vince

1/5/2006 10:02:22 PM

Ontario, Canada.

Heat activated, Auto vent window openers. Go to Lee Valley at the link below. I have used them for the past two years with great success.

http://www.leevalley.com/garden/page.aspx?c=2&cat=2,43224&p=10543

1/5/2006 10:30:36 PM

Billerica,Massachusetts

charleys greenhouse supplies also sells several different types.

Glenn

http://www.charleysgreenhouse.com/

1/6/2006 8:10:10 AM

Oz

If you look around some surplus home goods supply centers,you might find basement auto-vents for cheap.

1/6/2006 10:49:07 AM

Rhode Island

Farmtek.com has a ton of stuff too!!!!

1/7/2006 10:30:19 AM

Southeast Wisconsin

As a greenhouse person all of my life, I can advise you to put in a small exhaust fan on the west end and a small louvre on the east side, hook up one simple thermostat to control and you will have a well ventilate house. The vent openers are okay, but can get messed up with heavy snow loads and sometime it will vent when the winds are blowing 40-50 miles an hour and tear them up.

Russ

1/8/2006 11:59:35 AM

[email protected]

See the beginning of my 2005 diary for our greenhouse that is set up exactly as Russ has suggested. Thermostatically controlled lovered fan to the West. $10 louvered intake from Home Cheapo on the East.

The thermostat was $45 (Farmtec.com) and the lovered fan is $179 at Grainger though less costly versions are available.

Bigger is better. A LOT of spring damage is caused by cloches that are too small & accumulate not just heat, but also ammonia. See growers diaries for plants with no productive leaves left where the cloches were just 4-6 weeks into the growing season. Ammonia & heat!

1/8/2006 2:20:41 PM

Norton, MA

Ammonia? AleX Noel.

1/8/2006 5:49:43 PM