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Super Green Thumb
Posts: 7414
Joined: Mon Mar 23, 2009 1:59 pm
Location: TN. 50 years of gardening experience.

Green House Suggestions, Do's & Don'ts

I am interested in every ones suggestions on building a green house. I have a truck load of free windows from a company that does replacement windows.

Does a green house need a foundation?

How do I keep a big wind from blowing the green house over?

Should I put NO glass on the north side?

My plan at the moment is to build a 2x4 frame using pressure treated lumber then attaching the aluminum windows to the frame with screws. I want the south side to be about 6'6" tall with a shed type roof running up hill to about 8" high on the north wall. I mostly want this green house to grow tomatoes and a few other plants all winter so I can have fresh garden vegatables all winter long. I am thinking I will put a walk in door on the east wall with an isle down the center to the other end of the green house. The south side of the green house will be for planting plants all winter about 3 ft wide 40 ft long. The north side will be water barrel heat storage for after the sun goes down. A work bench above the water barrels 2 ft by 40 ft will be for potting plants and growing plants from seeds for the spring garden.

It will probably need a fan with loovers for ventilation if it gets too hot inside.

What are your experiences with green houses???????????

Super Green Thumb
Posts: 3062
Joined: Fri Aug 07, 2009 5:40 pm
Location: ohio

Well, I've never built one myself, but since no one has posted yet, I'll post these sites that seem to have a lot of good information on greenhouse construction

[url=]Building a Greenhouse[/url]

[url=]Greenhouse Building Resources[/url]

[url=]Greenhouse Plans[/url]

I hope these help you out, Gary.

Senior Member
Posts: 197
Joined: Wed Apr 27, 2011 11:11 pm
Location: Alaska

A foundation is nice, will help w big wind not blow it over :)
I used treated 4X6 s dug in with 2" above ground & filled inside area with gravel for good inside drainage.
Don't forget to have ventilation as it will get very hot on sunny days.
Fan & louvers on a thermostat.
Google green house ventilation fans, some sites help you size the fan for GH size
Sounds like a fun useful project.
Pictures as you build ??

Super Green Thumb
Posts: 2437
Joined: Mon Nov 15, 2010 10:31 pm
Location: Latrobe Pa.

OK lets get stared. You are in my ball park now! I probably think like you! The barrels or 50 gallon drums work best. Paint them black and have the fan blow air around them when the temp goes above 50! I would look for some old radiators or get 40 feet of baseboard heaters and connect a small water pump to them with a feed to one of the drums but put the return line at the other end of your drums!
Lets say you have 15 drums now you need to use the syphom method to move the water to all the drums. A small 6 foot hose will do that! As the pump pumps the water to the front drum the syphon moves the water to the next drum like a domino effect. You will be taking heat from the air quickly with the base board heaters and raising your drum temp as much as 10 degrees to give the heat off at night. The pump cost pennies to run! The drums will also take heat from the air to help cool the greenhouse n sunny days in the winter!
I would run a inside layer of plastic as your extra insulation and if its just cheap plastic used for only a year keep it around 3 to 4 mills so more light comes in! I have screens on the bottom 2 feet of my greenhose so I can open t to fresh air and no bugs get in! Last is that the pump can be turned on at night to heat the greenhouse when it gets below the drum water temperature or just leave it on all the time! Where you live you should be able to keep the temp above freezing without much expense using this method!

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Greener Thumb
Posts: 1855
Joined: Thu Jan 22, 2009 8:40 pm
Location: N. California

all you need to do is research passive solar greenhouses. which seems like you already sort of have the point.

then read the link in this thread.

Greener Thumb
Posts: 955
Joined: Sun Apr 04, 2010 3:29 pm
Location: Central PA

as mentioned, do some reading on solar design & factors if you intend that to be your primary heat.

ventilation: absolutely. dead of winter with snow up to your (...ah....whatever) a greenhouse can cook the vegetables on the plant - "look Ma - no pot!"

and the opposite of ventilation is cold air intrusion - gaps & holes will really zap you with passive solar. working with salvaged materials means extra specially attention to this detail

from the width you imply - bed + aisle + bench/drums - consider 2x6 for uprights and 2x8 for the roof beams/trusses/(whatevers) 2x4's are not adequate for that span - see "bending glass" below...

foundation: well, glass doesn't bend all that well - so a shifting structure made of glass does have a tendency to un-make your day. typically greenhouses are anchored to the foundation to keep them from going airborne - it does need to be anchored somehow - big sail area, not a lot of weight. keep in mind - glass only breaks in the dead of the night - typically on the weekend when you can't get stuff - and by morning you've got nothing but froze mush.

if you have the possibility to rig up a freeze alarm, that's a good move. _plan_ and _have on hand_ the stuff you need to "plug up a busted glass" - I kept remnants and duct tape - it can be that simple - but when you need it, you need it now.

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