How to Build a Lean-to Greenhouse for Under $100
How to Build a Lean-To Greenhouse on a Budget
DIY Lean-To Greenhouse Built with Salvaged Windows (Real Budget Breakdown)
Important context: This lean-to greenhouse was built years ago using reclaimed windows, scrap lumber, and leftover supplies from previous projects. Prices have changed since then, so this post has been updated to reflect what’s still realistic in 2026 — and how this project can still be done affordably today.
Our last freeze is late, so I wanted a dedicated space to start seeds earlier — somewhere better than my bedroom window.
Because I’m frugally minded and love upcycling, my husband and I challenged ourselves to build a functional lean-to greenhouse using as many materials as possible that we already had on hand. Our goal was simple: build it for under $100.
To get inspired, I headed over to Pinterest and found a simple lean-to greenhouse build plan that really spoke to me. I loved how the builder used what he already had on hand to create something functional — and that mindset became the foundation for our own greenhouse.
After gathering inspiration and taking inventory of what we already had — old windows, spare lumber, and hardware — we landed on a lean-to greenhouse design that worked perfectly with those materials.
Materials Used for This Greenhouse
- Reclaimed windows: Salvaged from garage sales and remodels
- Scrap lumber: Leftover 2×4s
- Exterior screws & framing nails: Mostly already owned
- Greenhouse plastic: Used where glass wasn’t available
Step 1: Choose a Lean-To Greenhouse Design
We chose a lean-to greenhouse design because it worked best with the windows we already had — especially one large window that became the roof. Lean-to designs are forgiving and perfect for reclaimed materials.
Step 2: Build the Walls Around Your Windows
Instead of cutting windows to fit a frame, we did the opposite — we built the frame around the windows. Each wall was assembled flat on the ground using 2×4s fitted tightly around the window edges.
The heights were adjusted so the back wall matched the highest point of the side walls and the front wall matched the lowest — this creates the lean-to slope.
Step 3: Secure the Walls Together
Once all four walls were built, we stood them upright and secured them together using exterior screws. This created the basic greenhouse structure.
The lean-to shape allows you to stand comfortably inside and makes ventilation much easier.
Step 4: Install Fixed and Hinged Windows
Each window opening was framed with simple wood jambs so the windows could be secured properly. Some windows were fixed in place, while others were installed with hinges for ventilation.
Step 5: Fill Gaps with Greenhouse Plastic
Where we didn’t have glass, we used greenhouse plastic. It was stapled tightly between two wood strips to prevent tearing and improve insulation.
Step 6: Build the Roof
The roof was built using a large salvaged window framed in wood and attached with hinges so it could open for ventilation.
Step 7: Add Shelving and Finishing Touches
Inside, we added shelving using cedar crates supported by simple wood rails. This made seed starting and transplanting much easier.
What This Lean-To Greenhouse Really Cost (Then vs. Now)
This greenhouse was built for approximately $67 using salvaged and on-hand materials. In 2026, a similar build is still achievable under $100 if reclaimed materials are used.
Lean-To Greenhouse Cost FAQs
Is it really possible to build a lean-to greenhouse for under $100?
Yes — if you use reclaimed windows, scrap lumber, and supplies you already own. Buying everything new would cost significantly more.
How much would this greenhouse cost if built entirely with new materials?
Expect closer to $150–$250 in 2026, depending on lumber and window prices.
There’s still time to build your own greenhouse — and you don’t need a massive budget to do it. Creativity and flexibility make all the difference.
Trending Diys
Comments
Leave a Reply
More Related Diys
Trending DIY Projects
- DIY
- Recipes
- Deals
- Blog
Report a Problem
Please select the problem you are facing with this deal:
- Price Increased
- Price Decreased
- No longer available
- Expired
- Link doesn't work
- Suggestion
- Compliment
- Other
Add more details:
Thank you for your feedback. We really appreciate it.
Enter your email address if you would like
to receive a follow up.
Please Try Again
Thanks for providing the email address.
We will reach out to you as soon as possible.
Popular
Recommended
About Us
At Fabulessly Frugal, our goal is to help you live HEALTHY, WEALTHY, and WISE! My team and I work hard to bring you the best, online deals, clean eating, DIY's, freezer meal recipes, and more! I LOVE coaching and inspiring people to improve their health in my fitness challenge! You should also check out my favorite cleanse! Learn more about me and the rest of my team.
Copyright © 2008–2026
Fabulessly Frugal: A Coupon Blog Sharing Gift Ideas, Amazon Deals, Printable Coupons, DIY, How to Extreme Coupon, and Make Ahead Meals. All rights reserved
I have about 30 old wooden windows saved up for this same project. It’s great to the actual process that you went through too. I love the idea of using greenhouse plastic for the odd shapes because mine will also be a lean-to. Can’t wait to get started!
I love this plan. I haven’t had luck with veggie gardening in open bins in the yard. Partly due to squirrels/rabbits eating it & cats using it as a litter box. We are actually going to he replacing our 1950s windows this summer & I think a permanant greenhouse for next year would be amazing (currently using a portable pop up one)
Melanie, you will have to share some pictures! I love spending an hour in the ‘house every day, just breathing in dirt-air and “watching” my plants grow. It’s my time out. 🙂 Have lots of fun and good luck!
I love this! And since I’m so into making new things out of old stuff, I had to show this to my husband. He’s the gardener, and he was quite interested too. We’ve built a sort of temporary greenhouse from pvc pipe and plastic, but this is more permanent. Thank you for sharing!!
Dana, this is awesome! You should come make one for me…;) Seriously I have been trying to think of something to keep deer out of a garden, this just might be it.
i JUST LOVED THIS STORY OF THE $100 OR LESS GREENHOUSE. WHAT A VERY SMART WOMAN YOU ARE. JUST WISHED I LIVED CLOSE TO YOU. JUST A GREAT IDEA YOU HAD AND LOOKS PRETTY GOOD TOO. KEEP UP THE GREAT IDEAS AND SHARE THEM TOO. GOOD LUCK WITH YOUR GARDENING. CAROLYN COTNER
thanks carolyn! we had a lot of fun doing it and are now reaping the benefits of having it. I have cucumbers, peppers, tomatoes, herbs, beans, peas, and pumpkins all growing in the ‘house now, just waiting for mid-june to plant outside. Happy gardening!
Love love love it! What size is it? It’s exactly what I have in mind.
It’s apapproximately 6×6 at the floor and its highest point is about 8 feet. Glad you like it!
thank you so much, your blog is just what ive been searching for, i had the plan of a recycled lean to greenhouse in my head but needed to know how to put it all together. My plan is to add a 12 x 5 deck at the side of my existing deck and build my greenhouse on it, so i can walk straight out the house and walk a few steps into my greenhouse. I am an avid freecycler and was lucky to be given several full length shower doors. I will have to buy the wood which will cost a little but nothing compared to buying a brand new greenhouse. once again, very grateful for your blog. 🙂
You’re welcome!
AWESOME! I had the same idea after I replaced a bunch of wood windows and now they won’t go to waste. Cool!!! I like your “design.” Thank you! A similar structure is in progress now in NE PDX.
We have wanted a greenhouse for years! I never thought of finding old windows to use. Great idea 🙂
Go for it! Thanks for your comment, Dacia.
Thank you for such simple but complete instructions! I do have one question: it doesn’t appear that you dug a foundation for your greenhouse. Living in Oregon, has your g-house had any trouble with frost heaving? I’m in northern Idaho. Some folks tell me I need a foundation below the frostline, others say I don’t. Wondering what your experience has been.
We didn’t dig a foundation… but with as much snow as you get, it’s probably wise!
I just had 19 Windows replaced in my house and asked the window guys to pile up my old windows with this very idea in mind. Thanks for sharing, I am building mine in a few weeks.
Brilliant!
You are awesome! Wonderful story. You and your husband Rock! $100.00 and looks like that. Great Job! Guess if you want something bad enough you’ll make it happen. Some day I will have one too. Just hope it looks like yours. Pretty cool thanks for sharing your story it helps by seeing pics. & gets me motivated to know anything is possible. Thanks again
So glad you like it!
Nice story. I am always looking for ideas on making a small but stand alone greenhouse. My dad has saved up windows from when he bought some new high-end replacement windows from his farmhouse. I was thinking something like this… And I have also used gutters for gardening. I love them for growing strawberries and herbs…. except that is horizontal growing… not vertical! 😉 Horizontal is left to right and vertical is up and down. 😀
We live on the Oregon coast and have a similar weather problem- this is a great inspiration! Thanks😊
Yay! I’m so glad it’s helpful. When you do it, share the pictures with us!
Did you hinge windows or the roof for ventilation?
Love that this is made from mismatched windows. Function over appearance is a great way to go but this really looks ok, too!
🙂 Right on Cindy!
thanks. i want to build a cat enclosure- so i would use ur frame and add some fencing or wire and sheet metal or wire roof.
Love it. I am thinking about building one.
Love it…live just east of you on the Idaho border. Want to build this against our pumphouse shed which is heated. Thank you for the detailed building pics, will help us alot!
How much time (approx) did it take you to build this? Thank you!
Love it