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greenhouse Started on my Greenhouse

W

wordwiz

Finally, I laid (actually erected) the corner posts of my hopefully 12x16' greenhouse. The plan is to use three 4x4 treated posts along with two 2x4 posts to support the back wall. The outside will be sheets of 4x8 boards, covered with plastic and an top layer of shingles. Inside, it will be insulated with R-26 fiberglass insulation, then covered with 2 mil mylar.

The back wall will be 7.5' tall, the front wall two feet less.

One nice thing - I don't have to be in a hurry. As long as I have the frame erected and the covering on the top within a month, I'll be on schedule.

Pix will follow but I need to create a gallery on my server. I've noticed that even with broadband, it takes quite a while for 20-30 images to load.

Mike
 
Gday mike, Finally there ! :woohoo: I look forward to watching your progress !

Compress you pictures to 40KB and they are realativly quick to upload.
 
Today, I picked up the lumber to finish the back wall as well as frame the front one. But... thanks to what seems like 40 days of rain and clouds, no way can I do anything until at least Saturday.

I have an air pump coming tomorrow that will easily aerate 50 five-gallon buckets but no roof or walls to put the plants now growing under/inside.

The goal is to have ripe toms by October 1, which may seem far off, but even early season plants take close to 70 days. That would mean Oct. 1

Looks like I need to get busy!

Mike
 
Wow, after 1.5" of rain since Monday evening, I figured my ground, that is dirt and not grass, would be a quagmire. It's not - in fact, dirt didn't stick to the bottom of my tennis shoes and sitting on it to pick a couple quarts of beans barely left any residue. So I got the hole dug for the posts for the back wall. Now I wish I would have picked up some Sackrete today.

Lots to do, not much time to do it in!

Mike
 
Great project you have going there mate.....Sounds like its going to end up being a great grow room...Good stuff!
 
Finally was able to get back to working on it. Nasty weather - every day I had a chance to work on it, it rained, and rained, and rained. Have all the posts (5) in the back up now and am waiting for the concrete to dry. The corner posts in the front are also in concrete - only five more to go. Have the plastic for the roof - 13 mil reinforced GH covering and the lumber for the back. Once the concrete sets, I can nail up the walls in the back. The west side will have two large windows that I can remove in warm weather, the east will have a door and large window but I won't be able to remove the latter. The front will be 8 mil, double layer polycarbonate.

Still need to run another wire that will support 20 amps to go with the one that is there. I want to use three 400-watt heaters (each one is suppose to heat 100 sq. ft. and my GH will be just under 200) but I figure the heat loss will be more than a normal home experiences, plus I need to run an air pump, have lights - hopefully not grow lights, just lights to see when it is dark.

The total cost to build it should come in well under $500, to build and fully equip to grow 52 plants under $1100 ($300 of that is just for the heaters). Quite an investment for me, much more than I would like to spend, but 50 plants producing 2 pounds of tomatoes per plant per week, selling at $1.25 per pound will take two months before I break even. Though next year, I would like to be able to replace the plastic roofing with the polycarb.

But on Christmas Day in the morning, I will be able to pick and eat a vine-ripened, real tomato as well as enjoy a BLT.

Pix once I start adding walls, rafters and coverings.

Mike
 
The back wall is up. The posts are in the ground about 18" deep with concrete making sure they do not go anyplace. The wall is four 7/16" 4x8' particle boards. The two outside and middle posts are 4x4, the other two 2x4. Two 2x6" boards run along the top to support the rafters that will be 2' apart. The one stud on the side is for the door.

greenhouse1.jpg


Here's from the side. The pole that looks horizontal is for my red noodle beans. They are almost done for the season though I still have a row of carrots growing in the middle of the GH.

greenhouse2.jpg


The rafters will be 12' 2x4" and will be covered with 13 mil reinforced GH plastic. The front wall will be twin wall polycarbonate. The side walls will be a combo of poly and glass windows/door which I can remove or open in warm weather. The back wall will be insulated with R-26 fiberglass (as will the bottom foot around the rest of it) and then covered with plastic. The other walls and ceiling will also be covered with six-mil clear plastic, giving me a 3.5" vapor barrier. I'm hoping to get by with 3 400 watt heaters, each one is suppose to heat about 100 sq. ft. I may need to have a kerosene heater for those few nights when it gets super cold.

So far, I have $231 invested in it. Still need the insulation, polycarbonate, six mil plastic, some framing lumber, wiring and the expensive part - the heaters. By the time I'm finished, probably about $800 total.

Mike
 
Hate you.

j/k ;)

I'm going to start amassing material to rebuild my greenhaus this winter as well. From watching craigslist as well as local sale boards, used thermopane windows are selling for anywhere from $1-$5 per square foot. We've got an instate energy rebate program that pays people to upgrade their houses for efficency, so there's a glut of perfectly usable double pane windows out there. I'm thinking for a 10 x 24 greenhaus I'll need about 260sf of glass, depending on how much glass I want to put on the East and West sides. So, I'm just going to start hording a mess of 52' x 48" windows- I figure about 15 of 'em ought to be enough! Another thing I'm going to do is pour an actual foundation. If I can find some Pex tube on the cheap I'll put that in the floor for future use to extend my season but the main reason I want a concrete foundation is for cleanup and sterility- dirt floors that are open to the outside world are a great vector for nasty bugs and fungii and the like. I'm thinking a bunch of bleach and a nice smooth epoxy finish on the floor with a French drain in the middle for easy cleanout. I'M SICK OF FRIGGIN' BUGS!!!
 
Hinky,

I look forward to reading of your progress! Are you going to use a double layer of glass or line the windows with plastic or bubble wrap? The best place for six-mil clear plastic is a paint store - it's less than half the price other stores want. Bubble wrap is also suppose to be great - you "glue" it to the inside windows using water!

Mike
 
hah!
I'd never thought about bubble wrap, that's a great idea! Hell, come to think of it, it'd probably be pretty good in-wall insulation as well. Great, now I'm going to have yet another pile of garbage out in the yard for future use, heheheh.
I'll be using double pane windows that are still in their frames like these. While they're older and less efficient than triple pane low-E windows, they still do pretty well at insulating (compared to normal fiber/plastic greenhouses!) on their own, plus I'll get all ghetto with this stuff on the inside of the windows once they're in place. It's ghetto but the stuff works really well and it's cheap.
It might take a while to amass the windows, but it'll be worth it. Double pane windows, a real (and insulated) foundation, and 6" thick insulated North wall and roof. Oh yeah, I also ran electricity and natural gas out there too. Maybe I can get out to a 6 or 7 months grow season out there! :lol:
 
Hinky, Have you thought about letting some light in through the ceiling? I know the sun stays rather low in the sky in winter but I would consider having at least the front half allow light in. Six mil clear plastic is not very expensive and three layers of it, each separated by an inch or two, will provide a very good barrier.

Mike
 
Mike...if you are not using treated wood in the ground with the cement, make sure you treat the wood at ground level for termites or in about 2 years, your GH will fall down...
 
AlabamaJack said:
Mike...if you are not using treated wood in the ground with the cement, make sure you treat the wood at ground level for termites or in about 2 years, your GH will fall down...
Click to expand...

AJ,

It's treated! At least the 4x4s and 2x4s are.

Mike
 
I am hoping to get the "roof" on it by Thursday if it doesn't rain me out. Need to nail up two 2x6 boards, then put up the nine roof rafters on. If I can get that done tomorrow, I'll put the plastic across the rafters the next day.

Several years ago, I bought some aluminum studs when I was rehabbing a bedroom. They were like a flattened "V" but I cannot find those now. Instead, they sell U-channel type. I prefer the former because they are the same width as the 2x4 and when really help keep the plastic tight. If I cannot, I'll have to use lumber but then I have to worry about replacing it (or painting it every three years or so). Of course, I can be very optimistic and plan on making enough money to allow me to replace the roof with polycarbonate. At today's prices it would be about $250 plus some nuts, bolts and ways to secure it. But wow - would it allow a lot more light in!

Mike
 
I got 5/9 of the rafters up today, which isn't bad since I didn't start until after 4:00 and had to take a break to run to the hardware store.

Tomorrow is the challenge: I need to stretch the plastic over the rafters then nail it down. I wanted 1x2 furring strips but the yard had only 1x3s. But the key to having it last more than a year is keeping it tight. The rafters are 2' on center (for the most part) and the idea is to get the plastic straight on the first one, then pull it tight, nail the furring strip down to keep it from moving, then move on to the next one.

Once I do, I can move the few measly plants I have started and that have not died under it.

gh826.jpg


Mike
 
Been a busy day. Got the four rafters up. I have some floor kit material, metal stuff similar to drywall studs - each are about five foot long so I used four of them to span the 16 feet. Screwed them into the rafters in the middle of the GH, giving it more stability. Started putting the cover over the top - what a PITA! It took a couple of hours to get the first rafter correct (between stretching it across everything, then getting it as close to square as I could. I'm using lath to secure it to the rafters, trying to pull it as tight as I can.

Got almost 2/3 of the rafters done but the rains came. Not complaining - it's been a couple of weeks since it has rained, maybe a record for this year. But I still would have liked to have the entire thing covered.

Next is putting windows and doors in, as well as the sheeting around the front and sides. In another week or so, I'll have the money to buy the polycarbonate for the front and part of the sides but once I get the cover on the top, I can start moving the few plants I have upstairs into it. Still have a row of carrots growing - I'll water them until they die - be it October of this year or next year! OK, I'll let them grow until I need the room.

Mike
 
Alas, the rain and temps overnight and today have had an effect on the plastic - it has shrunk a bit. About 5" over a 16.5' span. Not sure if there will be enough to reach completely across the span. I figure I can scab on a furring strip or simply cut another piece off the roll.

Took some light readings yesterday and today. Yesterday, there were large clouds in the sky and the outside reading was 34K lux. Inside, making sure I was completely under the cover, the reading was 20K. Today, under a bright summer sun, the reading outside was 100K, inside 46K.

I'm thinking I need to cover the back wall with Mylar, at least part of it. 20K probably is not enough for flowering plants, though it is close. Yeah, the sun will not be as strong this winter, but the sun will be much lower on the horizon, meaning more light through the front polycarbonate.

And my test has started. I have some seeds that have just sprouted and they are now in the GH. Some in potting mix, some in rockwool. At worst, they will be getting 23K lux during the day, more than they got upstairs this winter/spring.

Time will tell!

Mike
 
Got the covering over the top today and better yet, got to take a picture!

finished.jpg


AJ, you were right - the cover lets a good amount of light in. It's somewhat hard to tell from this photo, but it was taken at about 5 pm. This is the shadow that was cast:

shadow.jpg


And this is how the back wall looked:

backwall.jpg


I intend to cover it with Mylar, at least the middle 54". Found it online - 50 feet, 2 mil, for about $33 that includes shipping. The wall is 7.5 feet tall.

Needless to say, I am pumped about this endeavor! Stuck a tray of newly sprouted seeds in it yesterday afternoon and they are thriving. My game plan is to build a shelf, about two feet from the top along the back wall, that will hold 19 flats of 18 plant trays. That's 342 seedlings I can grow without having to spend any money on lights or electricity.

Mike
 
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