# Building a greenhouse from scratch and scrap



## Waterboy (Sep 20, 2011)

Using some scrap material, old sliding glass doors and windows, and some purchased supplies (cement blocks, wire cloth, 2 X 4s and roof tin,) we began Greenhouse No. 2 this week.

The finished greenhouse will be 15-1/2 by 5-1/2 feet along the south side of our house, actually attached to the porch, which was added onto the house by a previous owner, not a skilled carpenter. (The rest of the house is solidly built, a custom 1966 ranch. So please disregard the raggedy plywood exterior. It's only temporary.)










Our greenhouse project began with a simple drawing, followed by marking the site and digging a level base.

Digging the site by hand took almost two days. 









I thought I'd be able to keep most of the excavated dirt for the greenhouse, but it is mainly clay and small rock, so will be used elsewhere. The soil will come instead from a mixture of this year's compost and topsoil we gather from our woods.










To keep out moles and other small rodents, Darren "sewed" together two pieces of wire cloth by weaving a wire along the edges of the two pieces. The wire may not be necessary in all parts of the world, but, here in the Ozarks, it is the difference between having vegetables or not. It covers the entire floor and extends about 8 inches up the inside of the walls.



















Once the ground was smooth and level, we put down the wire cloth and a foundation of cement blocks topped with 5X5 beams. We banked the cement blocks on both sides with some of the excavated clay to keep them in place during construction. Darren also laid down a sheet of the old plywood porch siding on the wire cloth while we work in there.










We added a strip of plastic landscape edging along the inside of the foundation at what will be the growing-soil level, but only because the edging was given to us and will help to keep the wet soil away from the wood. It is certainly not necessary, though.

Next, the 2X4 studs went up, followed by the rafters. Today, Darren will put on the tin roof while I paint. A few months ago, we bought the used sliding glass doors at a junk shop for $10 each. They are about 4 feet wide and 6 feet tall, the perfect size for three along the south face and one on the west. The east side will have an aluminum storm door and another used window, about 3-feet wide and 6-feet tall.










The old porch window will be used in Greenhouse No. 1 that Darren built last year along the south side of the shop. The porch window opening is now a narrow doorway leading from the porch into the greenhouse.

The challenge has been to build a square and level greenhouse onto a very un-square and out-of-level old porch. Darren showed me last night the 2-inch difference in length of the west and east walls of the greenhouse.

The best part of projects like this for us is being able to do all if it ourselves, using recycled building materials and putting ourselves another huge step toward being more self-reliant. Besides the greenhouse, this year Darren built the pedal-powered PTO so we will always be able to get lots of fresh drinking water out of our own well without electricity, and now have a 450-gallon storage tank for rainwater for the garden. During drought, we'll fill the tank with well water so our plants won't be shocked by 50-degree water.

The 18- by 5-foot lean-to greenhouse Darren built along the shop last November supplied us with spinach, lettuce, beets, kale, mustard greens and bok choy from mid-December until May (and we eat a ton of greens every day!) By the time it got too hot in the greenhouse to grow greens, our raised beds were producing. So the greenhouse became a large and super-efficient compost bin. We kept it well-watered with rainwater, and in just 2-3 weeks our peelings and whatnot became compost - many weeks ahead of the outdoor compost pile.

Our very first greenhouse several years ago was actually an expensive plastic greenhouse kit, a real learning experience. It did not hold up in wind and within two seasons, the plastic windows were cloudy. We suggest that even if you have to hire someone for the actual construction project, round up some used windows or doors. They are inexpensive and surprisingly available.

We'll be posting more photos as we go, so stay tuned. (Posted by Mrs. WaterBoy)


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## Tweto (Nov 26, 2011)

Your Green house makes me jealous. I designed a green house last month that I should have done next spring. The idea of using the green house for composting did not occur to me, but it does sound like a good idea.


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## Bobbb (Jan 7, 2012)

For my next greenhouse I'm going to use more of these. My present greenhouse has only 1 and that's not enough, though I do have some sliding windows which I open to help with ventilation but that requires active involvement on my part. These little beauties work all on their own and without needing electricity.


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## Waterboy (Sep 20, 2011)

Does anyone know if it is OK to hang large mirrors on the back wall to reflect light onto the plants? I found a couple large dresser mirrors in a junk shop, but am unsure now if they would create too much light or heat in the greenhouse.

The photos below are of Greenhouse No. 1 on the side of the shed. The lean-to design used less material and has a deceptively large growing area. We bought the used 3' by 4' windows for $5 each. I used flat stones from the yard for stepping stones. Within a couple weeks, the stones were nearly hidden under plants. We draped the tarp over the windows when it got really, really cold. I heard of an easier suggestion that I haven't tried yet. That is to light a candle on cold nights. This greenhouse is 18' long, so perhaps I'll light a few candles as soon as it gets cold enough.


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## Waterboy (Sep 20, 2011)

The photos below show progress on the greenhouse - with the roof framed for metal roofing, and the first wheelbarrow load of dirt inside. The large flat rock on the cinder blocks will eventually be nearly buried in dirt and serve as a step to the porch. Painting has been delayed by wet and cool weather. But, typical for the Ozarks, temperatures will soar to the 50s and 60s after today.


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## Bobbb (Jan 7, 2012)

Think about putting stones or bricks or barrels of water into the greenhouse so that they can soak up the heat during the day, helping to prevent overheating, and then release that heat after the sun goes down. This thermal mass will reduce the temperature swings and help your plants.

Also, I see that these appear attached to the side of your house so I'd give some thought to protecting the walls to the humidity you should be experiencing inside the greenhouse.


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## Waterboy (Sep 20, 2011)

Bobbb said:


> Think about putting stones or bricks or barrels of water into the greenhouse so that they can soak up the heat during the day, helping to prevent overheating, and then release that heat after the sun goes down. This thermal mass will reduce the temperature swings and help your plants.
> 
> Also, I see that these appear attached to the side of your house so I'd give some thought to protecting the walls to the humidity you should be experiencing inside the greenhouse.


Thanks for the useful tips!


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## *Andi (Nov 8, 2009)

Bobbb said:


> For my next greenhouse I'm going to use more of these. My present greenhouse has only 1 and that's not enough, though I do have some sliding windows which I open to help with ventilation but that requires active involvement on my part. These little beauties work all on their own and without needing electricity.


I need one of those...

Mrs. WaterBoy, I look forward to more post!


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## Bobbb (Jan 7, 2012)

I have a few of those 55 gal garbage cans in my greenhouse. I buried them half way into the ground with the idea that the top half would heat up and create a convection loop in the can and take the hotter water down to the bottom of the barrel and transfer the heat into the ground. I haven't done any testing on how well this works in terms of heat transfer into the ground but it did moderate the temperate swings and it did slightly extend my growing season.

For your attached greenhouse the back wall, because it's not glass, is ideal for a whole series of stacked barrels, black preferably, to soak up the sun.


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## Bobbb (Jan 7, 2012)

*Andi said:


> I need one of those...


One? I'll bet you need more than one. Next greenhouse I build will probably have 10 or more. They are filled with a temperature sensitive wax and you dial in at what temperature you want the window(s) to start opening and then as the temperature rises above that point the window keeps opening more and more as the temperature keeps going up.


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## Bobbb (Jan 7, 2012)

Heat Source

Black 55 gallon barrels filled with water.
Rule of Thumb: 2.5 gallons/ft² of glazing for season extension or 5 gallons/ft² for all season.
How much do we need then?
12 ft x 24 ft = 288 ft²
288 x 2.5 = 720 gallons
288 x 5 = 1440 gallons
We have 20 x 55 = 1100 gallons

greenhouse heat source barrels

BTUs Released

1100 gallons of water weighs 9,130 lbs.
For each degree of drop at night, 9,130 BTUs are released.
At the Southwest Center, approximately 8 to 9 degree change is occuring so there would be 73,000 - 82,000 BTUs released.


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## *Andi (Nov 8, 2009)

Bobbb said:


> Heat Source
> 
> Black 55 gallon barrels filled with water.
> Rule of Thumb: 2.5 gallons/ft² of glazing for season extension or 5 gallons/ft² for all season.
> ...


Interesting ...

I use a 65 gallon rain barrel & 2 (smaller) 25 gallon watering tubs ...

Fact ...

My greenhouse will stay 10 degrees above outside temps. With the rain barrel added I have a extra 3 ta 6 degrees.  A sunny day will add a few degrees (around 6) and a cloudy or windy day 2 or 3 ...

Point ... a lot of different things come into play. (Just so you know )


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## Waterboy (Sep 20, 2011)

Planting day!










No sooner than Darren had placed the last sheet of glass on our new greenhouse was I inside planting. Of course, that was after we shoveled in many wheelbarrow loads of soil and compost to a depth of about 10 inches.

I managed to round up a few small lettuce, bok choy and mustard green plants from the raised beds that hadn't frozen yet, but mostly I planted seeds. I mixed up several types of seed, which is the same technique I use outside to foil bugs, although insects aren't a problem inside. I guess I just like to see the variety of plants side by side.

Mix the seeds together in a large bowl with several handfuls of dry sand or soil, and then sprinkle them onto the lightly raked soil bed. Rake them over as usual, and pat down with the rake. This is especially useful with tiny seeds to prevent wasting seed by pouring out too many at once. I've tried the salt-shaker method, but still had trouble controlling the flow.

In about 3 weeks, we'll be enjoying radish tops and some of the faster-growing greens. The greenhouse has already become the morning spot for sitting with a cup of tea.

As soon as the rain stops, I'll post a photo of the beautiful greenhouse exterior. It's a dramatic contrast to the old, lop-sided porch!


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## talob (Sep 16, 2009)

I built my greenhouse with used windows and sliding door a tip... if you mow around your greenhouse cover the bottom 8-10 inches of glass with something to protect it from stones the mower kicks out, dont ask me how I know this.


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## Waterboy (Sep 20, 2011)

We'll be adding shelves to the back wall later this winter and gutters to catch rainwater. The panel and vented door will be replaced, too, when we find a window to fit. But, just in time for some sleet, we've got the greenhouse enclosed. And seeds are already sprouting!

It's amazing to see how those dirty, homely sliding glass doors that were stashed in the shed all summer turned into such a lovely, useful addition to our little house.


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## Waterboy (Sep 20, 2011)

talob said:


> I built my greenhouse with used windows and sliding door a tip... if you mow around your greenhouse cover the bottom 8-10 inches of glass with something to protect it from stones the mower kicks out, dont ask me how I know this.


I'm sorry, but I can't resist asking. Did you break some glass?


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## Bobbb (Jan 7, 2012)

I did like talob and elevated my glass up off the ground. What you might consider is making a fence of hardware cloth. It lets light through but the tight weave of metal wire should be enough to stop flying rocks.


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## talob (Sep 16, 2009)

UMMMM.... well actually bobbb I didnt elevate the glass, and one little stone just spiderwebbd to whole door .... then it fell out, ever try picking up a whole door glass thats pea to dime size pieces?


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## smaj100 (Oct 17, 2012)

I always try to mow away from the house and fences for the first two or three passes then come back and go the other direction. helps spread the grass clippings back out instead of piling up along the house, fence and under the deck.


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## Waterboy (Sep 20, 2011)

Another one of our self-sufficient goals here is to buy a new hand pushmower. We looked at antique ones, but they are heavy and generally in rough shape. I haven't seen one of the new ones up close, but have read that the new metal is lighter and the blades are self-sharpening. I doubt if we could run fast enough behind it to kick up stones to break glass.

I was surprised to read recently that companies in England were still making hand mowers in the 1960s. I don't know when we stopped making and buying them in the U.S.


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## *Andi (Nov 8, 2009)

You can still get them from Lehmans and made in the US.

http://non-electric.lehmans.com/search#w=lawn mower


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## smaj100 (Oct 17, 2012)

*Lowes*



Waterboy said:


> Another one of our self-sufficient goals here is to buy a new hand pushmower. We looked at antique ones, but they are heavy and generally in rough shape. I haven't seen one of the new ones up close, but have read that the new metal is lighter and the blades are self-sharpening. I doubt if we could run fast enough behind it to kick up stones to break glass.
> 
> I was surprised to read recently that companies in England were still making hand mowers in the 1960s. I don't know when we stopped making and buying them in the U.S.


Lowes still sells and carrys the old pushstyle rotary mower's. Last time I paid any attention to them they were $150+/- and that was a few years ago.

@Waterboy Thats a really nice looking greenhouse.:2thumb:


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## mdprepper (Jan 22, 2010)

Homedepot has them for $84

http://www.homedepot.com/webapp/wcs...ads-_-pla-_-100329907&ci_gpa=pla#.UMUrF0bSiFk


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## fondini (Mar 18, 2012)

Very nice project!


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