First things first: Building a DIY greenhouse with old windows will vary from project to project. The process depends a lot on the size of the windows you source, as well as the area that you have for your greenhouse. Therefore, I’m not going to include any measurements with this post. This is going to be a helpful tips and tricks sort of post, as well as a divulgence of costs post. If you have any questions, feel free to leave them down in the comments below.
I do want to warn anyone attempting this project— this is NOT a beginner project and was much harder and took much longer than I anticipated. I don’t want to scare you off, but I do want to prepare you. If I didn’t have my partner, I could not have done this project. Although I really appreciate the upcycling aspect, this was physically a very demanding project. If it was just me by myself, I would have had to buy a greenhouse kit and call it a day.
In the video above, you can see the overall rough process, but check out the steps below for more info.
Step 1: How to source your old windows
There’s lots of places to source old windows, but I will admit, they’ve gotten more expensive than they used to be. People definitely see the value in old windows, doors and salvaged architecture now.
Sourcing ideas:
- Flea markets (Check out this post for some of my best flea market tips.)
- Craigslist
- Yard sales
- Junk yards or salvage shops
- Buy Nothing groups
First, I bought windows from my local Habitat for Humanity Restore and got a couple of free glass doors off of my local Buy Nothing group. It took a surprising amount of time to find inexpensive windows of the same size. I’ve seen projects where folks used windows of different sizes, and I’m not saying that can’t be done, but it does add an extra level of difficulty in the building process. By using windows of the same size, you are able to build one frame instead of many frames for the windows. If I were doing this project again, I’d start looking for windows AT LEAST 6 months in advance.
Step 2: Buying the lumber and other supplies
Next, we bought the lumber, the polycarbonate sheeting for the roof and the corrugated metal for the sides. I wasn’t able to source enough windows of the same size, so we used the corrugated metal on the bottom of the greenhouse. I’m happy with that because I think it will reflect light and keep it super warm in there. Right now lumber is extremely expensive (the price totals are below), but I will still a little shocked that an “upcycled,” DIY project cost so much.
Step 3: Painting the old windows and boards for the DIY greenhouse
I took a long time painting all of the boards and windows before we put it together because the windows had a lot of cracks and crevices. When we put it all together, I knew there was no way I could paint everything neatly. I also wanted to paint everything to make it look nicer and add a bit of an extra level of protection since this will be out in the elements.
Step 4: Actually building the DIY greenhouse from old windows!
Then, we leveled the ground. This is essential for creating a good foundation. If you have a concrete pad that’s nice, but not everyone is going to be able to pour concrete. Plus, that’s another expense. Some folks want to plant directly in the ground too– which concrete would prevent.
After that, we put in the posts in the ground and built frames around the old windows. Once the frames were built, we moved them into place and screwed everything together.
The poly carb roof went on next and then the galvanized metal. We had originally planned to make the entire front of the greenhouse from windows, but I stepped on one and broke it. D’oh! So we had to nix two windows from the front of the greenhouse.
Luckily, we did buy a little extra lumber and used that on the front instead. Again, lesson learned and if I had to do it again, I’d have bought extra windows, just in case.
Step 5: Finishing touches to the greenhouse and planting
After everything was built, I touched up the paint. Then I laid down a weed barrier and gravel in the greenhouse to prevent future weeds. Personally, I didn’t want to plant in the ground because the space I have the greenhouse in is a bit shady. I wanted the option to plant in pots and move plants out of the greenhouse, if needed. I also planted a grape plant that I can’t wait to see grow over the greenhouse. Talk about magic. Lastly, I added my plants and that’s it!
How much did my DIY Greenhouse with old windows cost?
- 14 Windows ($2 each): $28
- Wood, polycarbonate for the roof and decking screws: $447.37
- Gravel: $40
- Exterior Paint: free (leftover)
- Discount plants for the outside: $60
Total: $575.37
If I had more time or was able to source more reused materials, maybe this cost could be reduced some, but I did want to get this built before the fall when I need to store some of my more tender plants.
All that being said, building this DIY greenhouse with old windows was a difficult project, but I am incredibly proud of it.
For more DIY, repair and upcycled projects, I release exclusive tips and tricks over on my Substack.
This came out beyond gorgeous! So impressive. Haha I would definitely have to buy a greenhouse kit and call it a day.
I was tempted 😆
It looks wonderful! What are the dimensions, and what gardening zone are you in?
I am in zone 7A!
I’m obsessed. This turned out SO good!!
Thanks so much! I appreciate that.
This is AMAZING. You are so incredibly clever. Well done!
Thank you!
How did you make the door? Is it two windows put together? Great job it looks beautiful!
Yes, just two windows put together!
Beautiful! Where did you purchase the panels for the roofing? Thank you
Hi! They’re from Lowe’s.
Do you use the greenhouse all year? If it’s in full sun in the summer, does it get too hot? I have been saving some huge old storm windows for a similar project and am curious about best placement in my yard.
We do use the greenhouse all year! It’s not in full sun. There is a patch of trees off to the right that provides shade during the warmer months. We also leave the door open in the warmer months.
That’s an incredible price even with the high lumber prices. I’m more surprised by the $2 windows than the wood. Windows can be expensive. I fully expected to se 2k or higher. $600 range including plants is my kind of pricing. I’ll definitely building one of these in a couple years when I get my house.
Glad to hear it! Yes, I looked for the windows for a long time. Even windows on FB Marketplace and Craigslist were high, but I lucked out at the local Habitat for Humanity Restore.
Looks amazing! Have you had any problems with rain or snow collecting on the roof? I am starting a similar project in the spring and was originally planning on a sloped roof. A flat roof would make the build a bit easier, so wondering how it has been working out. Thanks!
Hi Jen, you might not be able to tell in the photos, but the roof is sloped. It slopes towards the back.
The project turned out beautifully. I could buy a green house but I want the shabby chic aesthetic that is achieved with recycled windows. Thanks for posting. Your project has really given me inspiration to tackle such a project with help of course!
Thank you!
Hi, first off, freaking awesome job!! We are in a similar gardening zone so can you tell me how the greenhouse is positioned in relation to the sun? I had a cheap greenhouse kit this fall/winter (future plans to do something like you did) but all of my plants got scorched and died. I apparently incorrectly assumed they needed as much sun as possible during the cold months. Any advice would be appreciated!!
The best place is usually to the south for the most sun, but if you’re having that problem here’s a few things that might help. A. This greenhouse actually gets shade from a neighboring tree during the summer. If you have a tree that can provide some shade, that may help. B. Some folks also use a shade cloth during the summer. C. You could just have portions of the greenhouse that have total sun. You’ll notice in my greenhouse, we have panels at the bottom. Those are reflective, but you could use solid wood to block the sun. D. You could also put a film on your windows to cut down the bright light. We used a film on our bathroom window to make it opaque. Hope this helps!
Hello! Love the greenhouse. Planning on tackling one this year. Can you please tell me when building frame, did you secure windows at just top and bottom of frame? Are the windows secured to each other as well? Thank you!
It’s all secured together!
This is great, Melanie! I am a (much) older gardener, and I already have sev. friends in line to build this project at summer’s end. I am even using the brown color! However, mine will be 12 x 18, have a heater and be used for tropical fruits in Zone 6A (guava, pitanga, blood oranges, Olives) So, well see how it goes! I wish we (my generation) would have had sites like yours ehen I was younger! Xour site is very cute, and has affordable ideas! Thank you for your greenhouse post! I tried to subscribe, but had a glitch – my email is debrabpitts#yahoo.com.
Thank you for reading and good luck with your project!