want greenhouse
 

Anyone in this forum know how to build an efficient but cheap greenhouse?

Efficient greenhouse might even be an oxymoron.

I worked a few months re-skinning and doing other work for a commercial greenhouse and really had my eyes opened and it certainly lessened my desire for one. They will frequently need a full blast of heat and later in the day the ventilators will be running full tilt.

Hot, humid, and tropical like was my opinion when watering even though the temperature was just above freezing.

I expect anchored hoops, solid endwalls (with doorway of course) and double poly inflated with air between the two layers is about the most efficient unit while staying reasonably priced.

The layers are inflated with a small motored squirrel cage fan. There must be a throttling valve on it to prevent over inflation. I have always thought that one could use an old auto defroster and limiting device to achieve the same results.

Some homemade units are set into a hillside for less heat loss and gain from berming.

I have also thought about using one of the polycarbonate units with a larger double poly unit built over the top to keep super cold air from it during the winter. Kind of like storm window principal. One could probably even plant spinach and other cold loving plants between the two units. Just dreaming what MIGHT work.

I have one of those hoop house type green house covered in plastic. It comes altogether as a "kit" type with all the pieces of wood with it. It was very easy to put up..can't remember what company perhaps..you can find it in one of the catalogs..cost around $300..have had it up for now over 5 years and plastic still resonably good on it. I put mine under a tree because in the spring the sun shines into it just fine..not too warm and as the summer progresses the shade from the sun keeps the greenhouse from getting totally unbearable with the heat. Keep that in mind when you put yours in place. Good Luck !!

If you go back a page in the discussion topics, someone posted a link with a whole bunch of building plans. You might like.

We have the same urge here at our little place, but not a lot of budget. We came across a contractor who was replacing all the windows in a local housing complex, and salvaged over 150 double paned windows.

We have cleared and are in the process of building the frame for it now, and we will be putting up glass pretty soon. It will be 10'x 30' and attached to the southern side of our trailer.
It has a perfect southern exposure, and will be a nice place to start seeds and extend our growing season. We have kicked around the idea of a wood burner in there for a heat source in winter.

http://i58.photobucket.com/albums/g2...r/100_2004.jpg

http://i58.photobucket.com/albums/g2...r/100_2002.jpg


We bought a sliding glass door for $20 and that will be access on one end, and regular door with a big window in it for the east end.

Not a lot of money tied up in it at this point, and hopefully we will have it done in time to start seeds this spring.

LesleyS, it rather depends on your approach and your goals. We built a very simple lean-to greenhouse out of 2x4's and translucent sheet plastic. It lasted for years and provided a tremendous amount of free heat to our house. It was also a play space for our young children, a place to raise rabbits and we grew a wide variety of plants in it.

We did not try to keep it warm during the night. That is key. Its primary job was to act as a solar collector for our home. We're in the mountains northern Vermont. We have a south east exposure. It cut our wood consumption from seven to four cords of wood a winter.

All the other things the greenhouse did were side benefits.

Figure out your goals and then how to get there.

Cheers

-Walter
Sugar Mountain Farm
in the mountains of Vermont
http://SugarMtnFarm.com/blog/
http://HollyGraphicArt.com/
http://NoNAIS.org

Might try googling hoop houses. I've seen plans for a few built with pvc.

I saw a permanent green house I am in love with AND the base was made from brick (helps hold heat longer) and the upper part from old windows. was about 10X10 or so

My plan *GRINS WIDELY* (yours too if you want) Is to salvage some old windows from construction sites the dump anywhere i can find em :) and invest the $ for the stone or brick or if your lucky enough for rock add that instead. for about 400.00 and some salvaging ( ingenious recycling if you like) you can have a very handsome greenhouse, if 400.00 is too much at present then I suggest ebay as I bought a very nice greenhouse for under 149.00 looks like a big tent LOL. but when i finally settle to new place......

Hi,

I think that one way to go that would be both cheap and efficient is to build a half hoop style greenhouse against a vertical north wall.
This way the north wall (and ends) can be insulated to reduce heat losses at night.

The other big improvement you could make that is pretty cheap is to use the scheme in which two layers of poly are used for the greenhouse glazing, and the area between the two layers is inflated with a small blower. This provides you with double glazing.


Lots of efficient (solar) greenhouse stuff here:
http://www.builditsolar.com/Projects.../sunspaces.htm

Gary

Using shade cloth rather than the shade of a tree would be way more beneficial. Most plants need FULL sun rather than indirect or shade.

I've been thinking of building a 10x10 greenhouse mainly out of salvaged double pane sliding glass doors (just the doors, not the metal frames). The frame would be four treated 4x4s at the corners sunk into concrete. Then build the frames for the sliding glass doors out of pressure treated 2x4s. Screws holding it together, not nails. The roof would be also sliding glass doors. Gables covered with cedar fence boards. Haven't drawn anything up yet, just thinking.

You can use 16' cattle panels , bowed into a hoop shape and fastenedt to a staked down 2X4 or 2x6(On inside of board), put up plywood ends with door in one end and vent fans in each end, cover the panels with poly secured to 2x's, cover that with poultry netting, smooth side toward plastic to hold it down.
Ed

Using glass doors.
 

You may wish to run your idea across the desk of a glass shop. Large expanses of glass such as that which sliding doors have are meant to be vertical not horizontal or on a slope. I wonder if the weight of the glass itself or from a snow load would cause it to break?

Also consider that many such doors would be treated to exclude certain types of light in order to limit carpet and furniture fading and to exclude heat. Will that work for you?

Might be good to run your ideas past a glassman.

DH made something similar to Whiterock's. Bent two 4 x 16 cattle panels over for an 8' long green house. The panels were tacked to a wood frame. The panels were then covered with clear plastic. Worked great. The only problem is that it is very light, even with the wood frame. We had a storm that blew the darn thing up in the air, into the woods in a kind of over the rainbow tumble. We managed to drag it back to it's place and added more tie downs.

Of course, it wasn't big enough. Last summer DH built two cathedral style greenhouses. I posted pictures of it last summer. Tall, beautiful. He got instructions online, can't remember what he paid for them. Right now, there's spinach, kale and some other greens growing in there.

How are you attaching plastic to hooped cattle panels?

pull it over the panels and staple it to the 2x's that are the base, cover with poultry netting, smooth side down, which is also stapled to the 2x's.
Ed

My husband got me a Rion Greenhouse Kit for our 25th wedding anniversary (a year and a half ago). The two of us put it together. I'm very happy with it so far. He ordered it from Sam's Club, but I noticed they are much more expensive by several hundred dollars now than they were then.

PVC hoops are a bad idea because gas evaporates off of the PVC and chemically reacts with the plastic covering. This weakens the covering. My neighbor has several acres of greenhouses and the first few were homemade PVC frames. Plastic is replaced every two years or so on the PVC frames but on wood or metal frames plastic lasts twice as long.

A double glazing, whether plastic or glass will save at least 30% in heating cost compared to a single layer. Modern greenhouses are still covered with double pane glass but the spans would be engineered for snow load. You can also use polycarboate or acrylic double wall panels but they are expensive (about $200 for a 6x16 foot panel).

If you are building a small greenhouse around 8x12, I would use used double pane glass if it was free or cheap. And I would get those automatically opening vents which have a gas filled cylinder which opens the vent when temperatures reach 70 degrees. In the summer you usually have more sunlight than the plants can use so blocking some out with a shade cloth or lath will help keep the greenhouse cooler.

Definitely keep sun orientation in mind when deciding where to locate your greenhouse. Here's a collection of plans to build a greenhouse.

This is the greenhouse I just finished building. I got laid off from work and didn't have much money to spend. I used all the scrape lumber I could find around the place. I covered it with reinforced poly that I traded a case of Mountain Dew for at a local construction site. Total cost I have in it is less than $50. It is about 8' X 8'.

OK, I tried to post photos, but can't figure out how. Can someone help me, please?

I have built two. The cheapest was nothing more than 4x4's laid on the ground which I drilled big enough holes in that 1/2" thin wall pvc pipe would fit tightly. I spaced the 4x4's 8' apart and used 18' pieces of pipe so 20' clear plastic would completely cover it.

The second is a little more fancy. I bought one of the one car portable carports from Harbor Freight. The kind that is covered by a tarp. I done away with the tarp and covered with 6mil clear plastic and for less than $300 I have a 8'x16' greenhouse.