Anyone built a greenhouse

[AndyF]

I'm thinking of building a lean-to greenhouse on the south wall of my barn and would appreciate some ideas from people who've already built one. I'm located in the Finger Lakes area of NY and have a zone 5 climate.

The greenhouse will be ~12'X24' and will be for starting vegetables for a market garden and may also be used for cold weather crops in the fall and winter.

I'm considering either inflated double poly or poly carbonate sheet glazing possibly over a metal frame (assuming I can buy some 1/2 arch greenhouse frames).

If anyone has built something similar let me know what your experience has been.

I've gotten real good advice on this board in the past and am hopeful that my luck will continue to hold.

 

[Turfman]

I have never built one, but have had two college courses in greenhouse construction and toured numerous ones to see construction techniques. I still have my texts for the classes so ask away and I'll try to look up the answers for you. They are interesting construction.

 

[wroughtn_harv]

The one I built for the boss was built for next to nothing in cost. I used tempered glass, shower and patio doors, and used redwood two bys surfaced.

It isn't as big as the one you want but when you consider the cost of getting stuff destined for the dump and the durability of glass it has worked great.

There are some pictures of it here on some thread. Steelfan was asking about it if I recall right.

 

[Steelfan]

Yep Woughtn_harv,

It was me. I think it was in your post with pictures of your wife's flower pot that you made. I found it. See if I can link it. Try number one. Go to <A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showflat.pl?Cat=&Board=photos&Number=158346&page=3&view=collapsed&sb=5&o=0&fpart=>here</A>


Kent

 

[Anonymous Poster]

Bein a bit north of you, South shore of Ontario, I had to build an emergency greenhouse this spring, when She who dreams of being obeyed, hauled in mater & pepper plants from Pensyltucky.
I used the bows from an old 12' satellite dish, and some perforated angle iron, and had it up in a couple hours. I put a single layer of 6 mil poly over it, and had no problem keeping the inside of the greenhouse 90+ degrees when it was 50 degrees outside, using no heat other than the sun.
Unfortunately, Her Gardnership, has now decided her tablegarden will be permanently greenhouse equipped.
Generation 2 will be a 2" tubing framed rectangle reusing the satellite dish bows for roof support, and one of the free roadsied pickup solar pool covers that look like bubble packing.
Wimmen can find a lot of projects that absolutely need immediate attention, especially when they know you can accomplish tthem.

 

[patrickg]

Andy, It looks like you have an offer of consulting services. I like Harv's approach with the recycled shower doors. No reason why your larger unit couldn't be made of old shower doors as well, for a lot less money I bet than other approaches.

A couple things, in case they might not turn up otherwise. Avoid glass that is too horizontal as even tempered shower doors are subject to hail damage. Consider plastic for the top glazing. From the pix, it looked like Harv put insulation on the wall at the back of his unit. Better than having a cold spot at night like from a metal wall. I would recommend that you consider a masonry wall lining. Could be simple. Dry stack old used cinder blocks, pin them with rebar and fill with dirt. Of course you could grout some cells if you need strength but a 2x4 vertically inside might be all you need to keep it upright. Borrow some strength from the existing wall and attach ties to it.

Why masonry? Well it will absorb a lot of light/heat without overheating. A wall covered with insulation helps heat the air during the day with sunlight (too much heat is a big problem with green houses). The thermal mass of the masonry wall will help moderate the temp, keeping it lower during periods of heating and warming the space at night or when cloudy and there is no solar gain. See also "tromb walls". In general, I would think it unlikely that you will ever put too much thermal mass in your greenhouse. I would recomend that if you opt for shelves that you consider something with cement blocks or similar as components for more thermal mass inside the space. Think of the thermal mass as a thermal flywheel that levels out the temperature so it doesn't get so hot in bright sun or as cold when there isn't sun. It is theoretically possible to use too much thermal mass but it isn't likely in your case.

Patrick

 

[Rubintropfen]

I helped my Dad replace about 1/2 acre of pre-WWII greenhouses when I was in high school in the late 70's. We used glass on aluminum spars purchased from, I think, <A target="_blank" HREF=http://www.nationalgreenhouse.com/>National Greenhouse</A>. Structural framing was heavy pipe welded on site. These houses work very well in all seasons (big old-fashioned boiler converted to NG in the late 60's or early 70's provides steam heat). Last I knew he was keeping different houses at 3 different temperature tiers during the winter (keeping tropical plants happy vs. starting annuals and Easter lillies, etc.).

The poly houses are probably no harder to heat than glass, but get much less incoming solar radiation than glass. My dad stores cut evergreens in one of the poly houses during the winter. Poly must be replaced every few years due to UV breakdown.

Sorry, I know nothing about poly carbonate sheet glazing.

You would probably learn a lot talking to somebody from the organizations that belong to <A target="_blank" HREF=http://www.ngma.com/>the National Greenhouse Manufacturer's Association</A>, even if you didn't buy anything from them.

 

[jsnitz]

I live over by Oneonta, NY. When I bought my house, it came with an attached greenhouse made from double insulated glasses for patio doors (just the glass, not the aluminum frame). You might look for some of those cheap or even free if the insulation seal is broken so the glasses are a little frosted up on the inside.

The builder used 4x4 timbers as framing between the glass sheets. The glass parts are about 3' x 6' and set horizontally in pairs. Starting at the house side, there is about 3' of regular roof, then a sheet of glass extending the roofline to the wall. The wall is slanted out at the bottom about 15 degrees, so the floor is wider than the top. Below the glass part of the wall is a regular wall about 3' high. The end walls each have a door and a little window, for cross ventilation.

Hope that explains it - no digital camera, so can't send a pic.

On a sunny winter day, we have to open up the door to the house to let the excess heat escape. In the summers, we have a shade screen (like some sort of netting cloth) that you attach on hooks on the roof to cover the glass to keep it from getting too hot.

BTW: it faces south, to catch the winter sun.

 

[wasabi]

Andy,

I built a small lean-to greenhouse out of sliding glass door panels, a salvaged glass door and lumber. It was a relatively easy project that has been enjoyable and satisfying. Look pretty good too. The only major problem is that, here in SC, it gets too hot to use in the peak of summer. All in all it has held up well for five years....except for an errant golf ball that managed to find and shatter one of the panels. I basically only use it now for orchids and hot peppers.

I have had fun researching and refining plans to build a larger, free-standing greenhouse at our mountain place, but the bath-house in progress is demanding current priority. When I do tackle it, my plan is to basically scrape down a suitable area, stake treated 2x12's for the perimeter border, taper backfill the outside borders (drain tile on the high side to vent runn-off around the hothouse), insulate from the ground and perimeter with blue-board, spread and tamp down clean gravel about a foot deep for the floor, cut, strip-bend and glue up 2x cypress for the main "hoops" (attached to perimeter) and use poly carbonate panels screwed down for the covering and ends. I know the poly panels will be more expensive, but personally, I just can't get comfortable with the film approach.... I've considered using a couple rows of blocks to increase termal mass, but think the gravel will suffice. I also may elect to run pipe under the floor and/or growing beds to provide supplemental circulating heat via an inexpensive water heater and small pump. This all makes sense to me, but talk is, well, cheap /w3tcompact/icons/blush.gif....I'll be in a better position to offer insights after I've actually built it.

Hope some of this will help you. Have fun!

 

[Steelfan]

Hi Jsnitz,

Welcome to TBN. Although I understand what you said here, I can't take credit for building a Greenhouse yet. W_harv is the man who started the post. I just linked it, and posted to it. W_harv is a handy guy to have around. I'd imagine that he could building anything, that he puts a mind to. Sorry for the shortcut on the name W_harv, but my fingers are getting tired. Thank for the info. This kind of stuff is what this forum is all about.

Kent