Introduction: Greenhouse From Old Windows

Picture of Greenhouse From Old Windows

This is a brief guide on how I took some old windows from houses they where tearing down in my neighborhood and turned them into a small greenhouse in my back yard. I collected the windows over the course of a year and a half and the build took about 3 months, spending one day a week on it. I spent about $300 for the lumber for the frame and screws, caulk, latches, etc. That's almost 10% of what a greenhouse kit would cost. The size I built was 7 ft high x 10 ft deep x 6 ft wide. But the size of your greenhouse will depend on your windows and the time you want to put into project.

Step 1: Collect Windows and Plan Two Pair of Equal Sides.

Picture of Collect Windows and Plan Two Pair of Equal Sides.

Look for old windows and save every one you get. After you have many, lay them out and play a game trying to make two pairs of "walls" both the same height. Two to three inches won't matter as you can cover the difference with wood. Smaller holes will need to have glass cut for them or filled with something else. Keep in mind that one end will need a door and the other a hole for a fan.

Step 2: Create a Frame

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Using the windows you chose as a guide, construct a frame for each wall. Use good lumber for this, as it is the structure that holds all the weight. I used all 2 x 4s for the studs and 4 x 4s for the corner posts. Choose a length that allows at least 14" of the stud to be placed in the ground for support.

Step 3: Brace Walls

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Start placing the walls up, bracing well so they don't fall over. Be sure to check that they are level.

Step 4: Make the Foundation Secure

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To avoid certain problems with pesky city building permits, I built the structure shed height and did not pour a concrete foundation. Instead I buried cinder blocks to stabilize the 4 x 4 corner posts. They keep it from moving an inch.

Step 5: Screw on Windows

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I used some nice coated deck screws to affix the windows to the frame. This will allow for easy removal and replacement if any break. This side facing the camera has the empty window for a fan.

Step 6: Get a Floor

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I was able to find someone who needed rocks removed from their yard. Using rocks or stones is good for two reasons: good drainage and heat storage.

Step 7: Build the Roof

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This was tricky. I ended up getting siding from an old shed someone had torn down. Any material you use, look for lightweight and waterproof material. Be sure that you have some that will open for ventilation, at least 20-30% of your floor space. You can get by with less if you use a fan for ventilation. Also build the slant roof with at least a 4 degree pitch, otherwise rain may not sheet off well.

Step 8: Add the Shelves and Fans.

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I found an old picnic bench table and this fan and shelf in the garbage. I figured I can use them in my greenhouse and save them from a landfill.

Step 9: Caulk and Paint

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Use a good outdoor caulk and seal all the cracks and holes between windows. Paint the wood to protect it from the weather.

Step 10: Update: Spring 2009

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The winter this year was especially bad near me. We had several feet of snow weeks on end. Luckily, I had already emptied the greenhouse and removed the roof panels in late November. I live in a zone 5 area. During the last month I brought out an electric heater to keep the temperature more consistent overnight.

This year I was able to obtain a large picture window and decided to install a windowed roof this spring. It will allow much more light in and therefore heat. I used the same deck screws to affix the windows to the roof frame I already had built. For the roof vents, I took two windows and screwed them together. I found old door hinges and used a piece of PVC as a brace. I added a screw holding it to the frame as a cotter pin. Lastly, In case a huge gust of wind came along and tried to yank open the windows, I nailed a small chain to the frame and window to prevent the window slamming backwards onto the rest of the roof.

I also modified the south facing bench. It connects to the frame on one end and still uses cinder blocks on the other. This will hopefully allow me to utilize the space inside better. It's filling quickly!

Now that the roof will allow so much light through, cooling will be a greater issue this summer. I may place some of the old panels back up in July/August to reflect some of that light. I also have obtained some reflecting fabric.

Lastly, I think in the future, I will completely rebuild the roof, using the windows for a gable type structure. It will force me to use some sort of poly material to cover up the gable ends. The current pitch of the roof is not enough to slope water off the windows completely.

Step 11: Edit: Fan Window

Picture of Edit: Fan Window

I was unhappy with having to remove the fan/vent window and having to prop it against something while cooling the greenhouse during the day. The frame was already designed to fit the window into it. I decided to have it slide up and be held in place. I started by salvaging some hinges from an old entertainment center. They are the kind that sit completely outside the door. Plus these had a unique shape that fit around a right angle. This allowed the wooden "stops" to swing in place and hold the window up while I was venting or when the fan is in place. Across the frame I nailed some boards to hold the fan window against the frame. Lastly, I found an old pulley and fastened it to the window so I can pull it up easily.

Step 12: Spring 2010 Roof Vent Upgrades

Picture of Spring 2010 Roof Vent Upgrades

Had a major score! A local community greenhouse was torn down and replaced. I was able to get some great parts. Here is a picture of the new window system. It originally opened the windows on the side of the greenhouse. The wheel is turned and rotates the gear attached to the pipe opening the windows. Makes opening and shutting easy. While every window now must be open at the same time, I can control the angle at which they are open.

Also pictured  is a gutter claimed from the trash. The hinge side of the roof windows always leaked profusely. The gutter catches the water and stores it in a bucket for easy watering.

Step 13: Spring 2010 Shading

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Bought secondhand some rolling shades which are working great. They easily roll up and down the south facing wall while not taking up too much room.

Step 14: Winter 2012

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Here is the greenhouse in a mild winter.  I overwinter many potted perennials inside. To insulate the roof, I stretch a sheet of poly across the top to keep out the drafts. Last October, 2011, I repainted both the inside and out. All the wood is doing well. I hope that, with care, the greenhouse will last over 10 years. It has changed the way I garden, making my back yard much more productive.


ClayD2 (author)2017-07-20

How could I do this with a bunch of half round windows ? I got a bunch of the half round ones given to me. Looking for a plan to use them for a greenhouse.

MacyW (author)2016-05-15

Using old windows can be hazardous, but with care and caution can be sucessfully done. You'd have to test for lead paint on evey window, and then use a proper respirator mask and a protective jumpsuit, remove the lead paint. I would soften it with a heat gun, and scrape away the paint with a painter's putty knife. All the while, this would be done on top of a tarp, laid out flat on the ground. Once all the windows are done, they should be completely re-grouted, primed, and painted with an exterior-grade paint. The woodwork ahould be completely encapsulated by new paint. This should prevent any residual lead from leaching out of the wood. Once everything is done, you can carefully disrobe and unmask, and then bundle them the lead paint chips and the tarp all up together. This will isolate all the lead bits from your yard, until there is a Hazardous Waste pickup in your area. In the meantime, make sure to prompty shower, with reapeated lathering up with soap, to remove any dust from your hair, body, etc.

It's a tedious undertaking, but it is a great way to preserve old vintage glass from the landfill!

Gee-Whiz (author)MacyW2016-05-15

Be VERY careful using heat on lead paint a friend hired "pros" to remove lead and they contaminated her house doing it that way. She had to throw out (not give away) ALL fiber items in her house (hat collection, upholstery, carpets, etc... Insurance covered it but vintage colle tables were ALL lost because of it!

EwaldG (author)Gee-Whiz2016-05-16

Another example of people watching too much TV and reading too much from companies that make money on your fears. If you expect your young kids to be chewing on your greenhouse, then you have more problems than lead in their diet. If you think the lead oxide in old paint is going to get into your food supply by leaching into your starter plants, think about how the "Greatest Generation" survived whole house coatings during their whole lives.

MichaelS189 (author)EwaldG2016-05-16

My house has asbestos exterior shingles. And asbestos insulation wrapped around the steam heating pipes. My grandfather built it, no deaths from cancer yet. Everytime i work on the house i expect to see the national guard sealing off the area. He is drilling a hole through the siding, run!
Lead paint was hazardous because it would chip and kids would eat it. So, you are correct. Unless your kids eat your greenhouse, you will be fine. Or, just paint it and seal in the lead

IronM7 (author)MichaelS1892016-05-22

Asbestos is extremely dangerous if you handle it. Left alone inside walls or on the exterior is ok as long as you don't drill a hole and release the fibers into the air where they will be breathed in by you or your family. To suggest that it is safe to handle it is little irresponsible as someone on here may read your post and attempt to do so.

EwaldG (author)IronM72016-05-22

Again; waving at the windmills.

There are several types of asbestos and not a few floating fibers of the worst kind are a reason to panic. People who worked for years in the mines were at risk. People who worked for years in the manufacturing industry were at risk. People who dig into a bit of ASBESTOS CONTAINING MATERIAL are not at risk. Stop and think! Since asbestos was used in nearly every home built following WWII, how are there so many of us still alive to be a threat to Social Security? Not enough? Consider the tons of asbestos that was actually ground to dust fibers and exposed to the air in the hundreds of millions of brake linings since 1950.

The 1986 ruling of the EPA was overturned due to its knee jerk nature. The fallout from those horror stories continue today; but to what end.

Now, if we could only outlaw latex and peanut butter.

gradecki (author)EwaldG2017-04-18

You do realize the difference between exposure to lead or asbestos and severe allergic reactions to peanut and latex, don't you?

EwaldG (author)MichaelS1892016-05-17

My office building was found to have asbestos "pegboard" as a cover for the ventilation ducts. It was painted maybe a dozen times over the years. An initial air quality evaluation gave a reading of 1.3 (in whatever units; we were not told). Total evacuation for two weeks by an army in hazmat suits gave us an all clear. The same air quality evaluation started at 10 and didn't go below 2 for ten years. The EPA told us that we were in a normal range.

OnaFarina made it! (author)EwaldG2016-05-16

yo! Folks, i am replying here to agree with this poster and to address the use of old windows.

I am the real deal. Look at my photos. Someone built my dream house, but, I'm a 57 yr old chick and I'm framing in each window myself, one window at a time. (He put in the fan, vents, roof), Yes, I suppose there is lead paint. I could care less. I am putting a straight bead of silicone everywhere I can. It's to ward off the wet. I live in Washington State. The windows that I am making open, will of course be drafty, and thats okay, free airflow. The plastic is doing great. I had to restaple one of the two upper triangles on the West side, the East teiangle of plastic is under the front porch roof, so it weathered the storms well, as did the sides.The "wrap" could go for a 3rd season easily and might have to if I can't get finished with the windows!

I'd be glad to answer questions. Fire away. I am in year 2 and it's a fertile place!

Peace my friends!

How awesome for you!! I'm nw Washington state, 54yr old widow (w/MS so doing most things takes me longer :-) )-doing my greenhouse alone too. I have 5 plastic framed lg windows a friend gave to me. They're dbl paned. Any thoughts on hardware (screws etc)? These windows don't open. I have 12 lg various RV windows -no frames. Do you think I can use them? How?
I would be so grateful for any ideas!
You're a huge inspiration, thank you!

Hiya PlantWhisper!
I don't think I can accurately or in good faith answer a single queston you have. Got ant guy friends your age that like to build stuff? You could look at all the stuff and formulate a plan. At least have someone teach you how to install a window. Thats what Zi fid, asked. friends husband. Maybe a class at Home Depot. On at least this. Also. I have only worked with wood framed windows, so trimming options that were available to me aren't for you. I wish you luck and hope your growing everywhere else on your property anyway!?

Thank you for your honesty & having a go at my questions! Yes it's green here indoors now w/ starts & purple outdoors w/ kale. I'm in negotiations with deer & elk just now to get a larger % of the crops for myself. They & my other neighbours, the raccoons, bears etc. apparently realize I'm a vegetarian. I've run while yelling 'shoo' at them (not the bears) in various languages. They don't flee in fear but seem to think I'm playing charades & it's their turn to guess.
I have had many yrs of diy though I'm stuck for ideas on this. Good use of the RV windows is a particularly tough one. I have researched these questions, but I find advice from someone like you & other diy'ers with real experience in such a project is so valuable! Especially as you're a fellow pacific northwestern gardener. Thanks again & have a great gardening year!

MichelleS60 (author)OnaFarina2016-07-06

How inspirational! I have been collecting wood windows for years now. I Love how simple & unique this looks. How big is it & about how many windows did you use? I know they're not all the same size but can you at least tell me approx how many small, med & large you used? What are you using as a door? What is the biggest window that you have?
Appreciate you being willing to let me ask so many questions. I seek knowledge.

OnaFarina (author)MichelleS602016-07-07

hi Michelle!

Scroll down to the first photos of my greenhouse. In the stuff I wrote, I give it's dimensions and you can see the door. (If you have trouble finding the original post and photos, let me know)

I have approx. 40 windows. All wood framed and very old. Very few are the same size. Well, not all windows: I do have 2 very large ,(sliding glass door size) windows that I will use down low laying long ways.

Wood:About 20 are large, approx. 30x30. Most are medium at about 12x18. None are smaller than that.

When I get to a spot where I have no window that works, I am just putting in a piece of the hard plastic sheet that was used on the roof, or just a piece of plywood to fit, (painted it will look fine).

I love that I inspired you. Use those windows!

It's not the easiest project I've ever done, lol, but, as long as I can keep installing windows at my own pace, keep that plastic wrap in good shape and grow tons of food at the sme time...I'm one happy lady!

Feel free to ask away!

Good luck!



NancyH6 (author)EwaldG2016-05-16

Could not agree with you more!


MichaelS189 (author)Gee-Whiz2016-05-16

I would have just put on a mask and gloves and shook everything out, outside. But, i have a house with asbestos siding, so i guess i am a daredevil.

OnaFarina (author)2017-03-29

Please know that the cover photo of an all window greenhouse is not the one I, OnaFarina, built. Scroll down and see mine after it was built. It is stick built and large and awesome with a tall roof, but is still wrapped mostly wrapped in plastic and there are photos of what windows I had installed when I wrote the post.

LindaP114 (author)2016-10-28

Lead paint can be contained with a good double coat of exterior paint or exterior grade clear "varnish" this will keep your shabby chic look

SophiesFoodieFiles (author)2016-10-19

Waw, well done! It looks fantastic & beautiful to have in the garden too! :)

tallulah_B (author)2016-05-15

Someone commented that a cement floor should be put in, but as was stated in the directions - City approval is required in most places, to put a structure on a cement floor so he used cinder blocks to put the posts in. I suppose he could have also put some cement into the bottom of the blocks, so wood would not touch ground.
As for the lead paint - that was only used on windows of a certain era, correct? Getting windows of a later era should stop that being an issue.
I like the up-cycling of the windows, stones, and old greenhouse parts - what an Awesome amount of re-purposing items that others no longer want/need. Talk about "one man's trash is another man's treasure"!!!!

IronM7 (author)tallulah_B2016-05-22

That's what I was thinking. Sink the cinder blocks in the ground a bit, place your 4x4 posts in (square them up) and pour cement into the hole. I think I'll lay ground cover then grab some patio stones that come on sale and use that as a floor. Maybe use 4x4s along the bottom outside edge of the structure as well, be a good, solid base I should think? Then frame away...I'm still trying to figure out what to use for 'glass' as old windows seem to be all the rage now, they're expensive!

tallulah_B (author)IronM72016-05-22

yes - as new windows get more expensive, more & more people are turning to recycling companies to get their windows. And if they have an older house these would keep the "flavour" of the older home. Triple paned windows are not only expensive but don't match homes of older eras.
I would want to know where the recycling companies exist that don't charge an arm & a leg for old, recycled windows! They're becoming increasingly rare!

ColleenW30 (author)tallulah_B2016-10-05

....or you could do what we did. There is an abandoned (repo'd by the bank actually) house next door that was built in 1900. We bought it to demo for the lot. I'm scraping EVERYTHING I can out of that house before the bulldozer and backhoe come. Windows, doors, (for a greenhouse build project) brick basement walls (for a grill pit, later) Anything I don't use and is worth $ to get out, i'm having a reclamation company come get it and pay me for the pleasure :)

OnaFarina (author)tallulah_B2016-05-16

to reply only to the foundation part of this convo. My guy poured an 1' wide x 2' deep footing of my footprint and put the future 4x4 post braces in. Done.

OnaFarina (author)OnaFarina2016-05-16

and, you are so right about the trash to treasure. My Windows were all donated and boy! did I Dig through peoples barns at their "garbage" and I now I have wonderful,local,vintage windows!

Kinnishian (author)2016-05-15

Occurs to me--> Do you really need to seal the cracks if you always want to keep some air flowing? Perhaps without sealant you get close to the airflow necessary? To get air flow out you can have a centrifugal fan blowing IN which distributes the air out the cracks?

EwaldG (author)Kinnishian2016-05-16

The primary purpose of a greenhouse is to modify the ambient temperature to benefit your plants.

The "greenhouse effect" is to allow visible light to enter the structure and warm the interior surfaces. They, in turn, will radiate light in the IR due to that surface being so much cooler than the sun. Window glass allows visible light (that's a good thing) to pass; but it blocks IR. That traps heat in the enclosure and makes it warmer for your plants.

This is all good for those cool days, but can cook things on a warm sunny day. THAT is why there needs to be a way to vent the hot air. Ideally, you can have an automatic opening (at some cost) or you can be diligent in doing it yourself. In my experience, I will forget to open or close the vent at some time during the season and lose some plants. Watering falls under the same category. So all the auto features are great but add to the cost.

Kinnishian (author)EwaldG2016-05-16

While I agree with the statements you're making, as they're generally correct, I don't see how that is a response?

I did indicate airflow. I'm just saying that what is the point of *sealing* your greenhouse windows, and then proceeding to make a hole for ventilation. Why not just ventilate using the holes that exist and positive airflow?

Granted, I think the answer is obvious, that my suggestion is much harder to control and requires slightly stronger fans. Still, it seems worth asking if anyone has tried that. Especially if it makes eventual greenhouse disassembly and reconstruction much easier.

EwaldG (author)Kinnishian2016-05-16

I think the point in the original post was to re-glaze the windows to hold the glass in place and to avoid cold air getting in. It is not necessary to provide air flow through the structure. Venting is important when it gets too hot. In that case, convection is enough and does not require a fan.

spencdood (author)EwaldG2016-10-02

just turn the windows around so the inside is facing outwards.

OnaFarina (author)EwaldG2016-07-07

my greenhouse will be heavily sealed at every window. I need to control the temperature, breeze, etc. just like a "real" house.

I have a high vent that is chocked open 24/7/365. I have a fan installed diagonally across from it on a thermostat. I keep it's vents propped open during growing time. I open the door EVERY morning during Spring/Summer growing season and shut it every night. I also have 2 pop-up roof vents that also stay open all Spring/Summer.

Do not go cheap on vents, fans and thermostats in a "real" greenhouse like mine. They are THE most important items in there!

OnaFarina (author)EwaldG2016-07-07

my greenhouse will be heavily sealed at every window. I need to control the temperature, breeze, etc. just like a "real" house.

I have a high vent that is chocked open 24/7/365. I have a fan installed diagonally across from it on a thermostat. I keep it's vents propped open during growing time. I open the door EVERY morning during Spring/Summer growing season and shut it every night. I also have 2 pop-up roof vents that also stay open all Spring/Summer.

Do not go cheap on vents, fans and thermostats in a "real" greenhouse like mine. They are THE most important items in there!

diy_bloke (author)2016-05-15

I was wondering if it would be beneficial to have a small stone foundation, maybe if only a row of briks for the wood to rest on, just to get it off the ground. (yeah I know, a bit late for you as yours is already up :-) )

OnaFarina (author)diy_bloke2016-07-07

it has a poured concrete footing. The inside is dirt floor covered with 3" of gravel.

None of the framing lumber or wood window casings touch the ground.

diy_bloke (author)OnaFarina2016-07-07


mlaiuppa. (author)2016-05-15

Excellent example of reuse.

And with your greenhouse you can start your spring seedlings much earlier in the year.

While it's too small for even a dwarf citrus in a pot, you could keep tomatoes going for quite some time in there.

OnaFarina (author)mlaiuppa.2016-07-07

i'm not sure which greenhouse you are talking about. Mine has a 12' high roof.

And yes, it is the perfect for seedling starting, I use lights to get thing started early.

I have citrus growing in pots and my tomatoes, all 30 of them, are growing vertically on strings, (youtube that, it's amazing and easy) and below them, all the way around are lettuces, leeks, radishes, onions, and some herbs and other stuff too!

OnaFarina (author)mlaiuppa.2016-05-16

exactly what is going on over here! I really dig having a greenhouse. We have already had full chock full of goodies out of there already and it's still raining every week and stormy! (Washington State)

OnaFarina made it! (author)2016-03-06

****see my post below****

Please everyone...Check out my post below...

look and reply!!



violetsmuse (author)OnaFarina2016-05-16

I love this one! The one above with the windows seems too strenuous for me, {arthritis}. I can easily have someone make this, thanks for sharing it. One question though please. Michigan Dave states that he's seen "changes over time". Am I missing something or are there more pictures somewhere that I've not seen?

OnaFarina (author)violetsmuse2016-07-07

no Violet, your not missing anything. His statement, (michigan dave), was about the plastic changing over time. Yes it will need replacing eventually. As it is getting brittle after 2 years of "weather".

However, if you've read this string, you'll see where I addressed that.

diy_bloke (author)OnaFarina2016-05-15

looks great. Mainly plastic walls it seems. Does that last long? I get the impression that after 1 or 2 seasons it is already brittle and the wind may tear it apart. Looks great though and probably not too expensive to replace the plastic

OnaFarina (author)diy_bloke2016-05-15

There are no plans. Sorry, Liz. I made it up and a local contractor built it. Just go for it.
Diy_bloke, the plastic needed to be stapled back in a few places from winter storms. It looks like it will make it another year, easily. It is not yellowed or brittle...yet.
I am slowly putting in windows all around. There will also be plexiglass and plywood panels. The plan is to have no plastic.
Thanks everyone!
Trying to post pics of the windows that are in...stay tuned.
Most is abundant already!

Lizabeth G (author)OnaFarina2016-05-15

Nice. Love the sitting area in the front. Are there plans out there?

MichiganDave (author)2016-05-15

This is a great 'ibble. Showing the changes over time makes this far more instructional to me. Therefore a BIG thanks for sharing with us all.

OnaFarina (author)MichiganDave2016-07-07


Your Welcome!

franwiedenhoeft (author)2016-06-30

Wow, I have to try this.

vkmcgee2 (author)2016-05-15

I really want a green house but wood frame houses are not the norm here in the desert. I've saved a bunch of windows but they have metal frames. The question is how to put them together? Anyone made a green house with windows like that?

OnaFarina (author)vkmcgee22016-05-16

Hi, I am going to use some metal framed windows in my greenhouse.If you look at the photos I have posted in this thread zoom in on how I put them in. I'm doing the metal ones the same way. A 1" wood stop that I nailer gunned around, runs all the way around each window, you can see the inside ones, but know that I did it on both sides of the window. I am going to 1" wood frame the metal ones the same way. Just as if they were a wooden window. I have not had to nail or screw into a wooden window frame yet, so I figure the metal frame makes no matter.

Good luck, just go for it!


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