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My Greenhouse Building Process

How I Built an Affordable and Inexpensive Greenhouse

greenhouse frame

Hello and welcome! I absolutely love my diy greenhouse and I want to share how I made it so you can build one too. It was inexpensive, and is possible even if you don’t have prior building experience (like me). There are many ways to build a cattle panel greenhouse; mine is just one way. If you're looking for ideas on how to build a greenhouse cheap, I encourage you to search for other examples of cattle panel greenhouses and then decide what will work for you.

 

As for the numbers: my cattle panel greenhouse dimensions are 8’x12’ and about 7.5’ tall in the center; it cost me somewhere around $800 U.S. dollars, and it took me 6 weeks to build. You can build a much cheaper greenhouse, and I’ll point out those opportunities in the explanation below.  You may also be able to build it quicker; I'm one person with a full time job and kids.

How warm does it stay in the winter? How hot does it get in the summer? I'm in Zone 6b and on a sunny day in the winter the temperature will rise about 30 degrees above the outside temperature. This is heaven when it’s 30-40 degrees Fahrenheit because the greenhouse feels like a spring day.  It's situated on the north side of my house and is partly in the shade so your results may vary. On cloudy days, the greenhouse temperature is about the same as the outside temperature - but minus the wind and minus the frost. I don’t heat mine, but some people do. For cooling and airflow in the summer, I use an outdoor-rated fan. To lower the temperature a little more, I hung burlap overhead. All of these items are listed on the Greenhouse Materials List page.

 

4x4 Posts cut to 19"

A note about tools: If you are new to using power tools (I was) please watch Youtube videos on safety before starting your own DIY greenhouse! If you want to avoid power tools, you could ask a friend to make your cuts as you need them. This was my original plan until my friend showed me how to use a circular saw. The only power tools that I used were the circular saw and a power drill. I found it really helpful to have two drills - one to drill the pilot hole and one to add the screw. Otherwise I would have been constantly changing drill bits. (Pilot holes prevent the wood from splitting when you drill in a screw, and also make it much easier for the screw to go in. The drill bit should be slightly smaller than the screw diameter. If you’re usure of what to use, don’t hesitate to ask a store associate - I did that many times!) And don’t forget safety glasses. :)

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Now, let's get to the building process of how I made my greenhouse from scratch and out of wood. It's written by and for those of us that have never built anything (me), and aren't sure where to start. I hope this helps you to see how it can be done.  I’ve broken down my building process into numbered steps so that it's easy to refer back to. A full list of everything that I used can be found on the cattle panel greenhouse materials page.

If you'd like more detail than what is below, including cut dimensions for all lumber and easy-to-follow instructions, consider purchasing the Greenhouse Building Guide.

1. Deciding on a Cattle Panel Greenhouse Design

My greenhouse has 20” high wood walls; some cattle panel greenhouses don’t and the cattle panels are attached to a 2x4 on the ground. I decided to build wood walls so that the greenhouse "ceiling" would be taller and have more head room, so that it would be heavier and less susceptible to shifting in high winds, and to allow air flow between the boards of the wall. Also, I really like the look of walls - I think they add to the greenhouse charm.


I did not set it on a foundation, nor did I anchor the posts in the ground. I did attach rebar to the long sides and anchored those in the ground. In some areas, a building permit is required for structures that have foundations, and isn’t required for moveable structures, so you may need to take that into consideration. My greenhouse would be considered moveable. At the time of this writing it's been up for 1.5 years and I haven’t had any issues with it shifting in the wind. Having said that, if you build one on wide open property with no wind breaks, you may need to anchor it to the ground more than I did. I live on a city lot and while the winds do come whipping through, it’s situated 16’ from my house, 2’ from my garage, and various trees and fences act as additional windbreaks. I decided on a size of 8’x12’ because boards come in 8’ and 12’ lengths and because you get a nice height when the 16’ panels arch over 8’. And finally, I chose a design that had no angle cuts. There are some designs that have angled 2x4’s on the short sides by the doors. These look great, but would have added an extra challenge for me.

 

Note for you beginner builders:  I knew that I would need a strategy to keep from getting overwhelmed with this backyard greenhouse. So I decided that the final greenhouse structure only had to be two things: 1) it needed to be safe and sturdy, and 2) it needed to be cute. If I could accomplish those two things, I would be ecstatic. Since that was my focus, I didn't worry about long it might take me,  or if my lumber cuts were imperfect, or if I had to redo a couple things as I learned.  

2. Making the 12'  Greenhouse Walls

My first step was to make the two 12’ sides. I used three 1x6 cedar boards (12’ length) for each side and attached them to four 4x4 cedar posts that were cut to 19” each. The top 1x6 is set about an inch higher than the top of the 4x4's to  give the cattle panels a ledge. I used a circular saw to cut the 4x4 posts. Zoom in on the first picture to see some pretty terrible cuts! My cuts got a little better as I went, and I just hid the worst ones as best as I could. I used deck screws to attach the boards to the posts. I left about an inch of space between the boards for airflow during warm weather.

Notes: Cedar is the most expensive option; treated lumber is less expensive; pallet wood can be free. My friend that built one and inspired me used free pallet wood that she already had. I used cedar because I didn’t want to spend time hunting for pallet wood and I didn’t want to worry about chemicals leaching into the ground from treated lumber.

Also, there were many times when I didn’t know what type or size of screw (or other material for that matter) that I needed or the name of something. So each time, I just explained to a store employee what I was trying to do and asked for help. Most people were very helpful.

4x4 posts

4x4 Posts cut to 19"

greenhouse side wall

12' Greenhouse side wall (1x6's screwed to 4x4 posts)

3. Connecting the Side Walls and Adding the Mulch Floor

I connected the 2 sides with an 8 foot 2x4. The 2x4 buts up against the 4x4 and is attached with steel angle brackets. I didn't take nearly enough pictures while I was building so many of these pictures were taken a year later.

 

I leveled the ground a little here (I probably should have done a little more). I set a level on all the sides and then shifted the dirt around a little so that the frame sat on the ground better. 

 

I went ahead and added mulch at this step to create the greenhouse floor because I didn’t want the area to get wet and muddy while I continued to work. I laid down two layers of cardboard to kill the grass and then added several bags of cedar mulch on top. I love using cedar because it smells really nice, it lasts longer than other mulches (it breaks down slower), and because it naturally repels some insects. Other nice floor options include pea gravel, pavers, or a combination of these. Mulch was cheap, easy, and quick.

4x4 Posts cut to 19"

12' Greenhouse side wall (1x6's screwed to 4x4 posts)

8 Foot 2x4's connect the greenhouse sides

Steel angle brackets connect the 2x4 to the 4x4 posts

greenhouse post brackets
greenhouse 2x4's

4. Attaching the Cattle Panels to the Wood Walls (there are three)

I was anxious to get this step underway. I wasn’t sure how difficult they would be transport and move around. I'm glad to say it was much easier than I expected and I put some tips in the notes below. Once I got them home, I started by attaching the middle panel first, by nailing it to the 4x4 posts with galvanized fence staples. The second and third ones were a little harder since they overlap the middle one by a few inches. The whole arch overlaps and metal doesn't stretch lol, so it just took a little finesse - and a second person to help hold and maneuver them. For reinforcement, I cut pieces of plumber’s pipe strapping to attach the panels to the 1x6 greenhouse walls. I used zip ties to attach the panels to each other. I did have to take out a few staples and redo them which meant buying this fence staple remover

 

I want to point out here that when the panels are arched and attached to both sides, they put outward pressure on the sides and cause them to bow. I found it helpful to use tie-down ratchet straps to pull the sides in while I attached the front and back frame. The shape of the arch fixed itself once I added the front and back.


Transporting the cattle panels was easier than I expected. They are 16’x50” and weigh 32 pounds. They fold into an arch pretty easily and I was able to carry them myself. They will probably fit in your (or a borrowed) pickup truck. If you don’t have access to a truck, you can rent a truck and pick them up. That’s what I ended up doing because I was worried that I would scratch a friend’s truck. Next time, I would borrow a friend’s truck - it wasn’t as difficult as I thought it would be. You’ll get some good ideas on how to transport them by searching YouTube.

greenhouse fence staples

2 Fence staples secure these panels to a 4x4 post

greenhouse cattle panels

Metal pipe strapping to secure panels to 1x6 boards

greenhouse zip ties

Zip ties hold the overlapping cattle panels together

greenhouse cattle panels

2 of 3 panels; sides are bowing slightly due to pressure

5. Starting the Front and Back Walls, and the Greenhouse Door Frames

Next I added three 1x6 boards to the front and back walls on one of the sides. To know how long those boards needed to be, I needed to know the size of my door frame. See the next step for how I figured that out. Once I knew how wide the door frame was going to be, I measured for the 1x6 boards and had them cut at the home improvement store. If you are building this by yourself, you’ll want trigger clamps to hold the wood in place while you screw the boards into the 4x4 posts. I also put up one side of the door frame so that the side boards could attach to it. To attach it to the bottom horizontal 2x4, I used another steel angle bracket.

4x4 Posts cut to 19"

greenhouse end wall

1x6 Boards on the front and back

greenhouse door frame

Metal bracket securing the 2x4 door frame to the base

6. Measuring the Doors and Door Frames

I bought my doors, rather than making them, for a couple of reasons. First, I knew that pretty, professionally-made doors would instantly help my greenhouse look better, no matter how the rest of my workmanship looked. Second, I was already a little overwhelmed with figuring the whole thing out, and the thought of having to also build doors was a bit much. Purchasing those decreased my work and helped me finish quicker. But you can definitely save money by making your own.

What size should the door frame be? This was the trickiest part of the whole process for me. I really wasn’t sure how much space should be left between the door and the door frame, or how tall the frame should be. I was concerned about the door being too tight when it closed or, conversely, about the gap being too big. I wasn't sure of the height, since I needed the cattle panels to rest on the corners. I’m SURE there are better, more efficient methods to figuring this out, but here’s what I did. I laid the frame pieces and the door on a flat surface (for me this was my driveway). This helped me visualize what it should look like and how it should work. I laid the hinges on the door so I could see how much room they needed. I positioned everything so that there was a small gap at the bottom, a small gap at the top, and a small gap on the side. Then I took measurements. Then I measured again just to be sure.

7. Finishing the Door Frames

With one side of the door frame done, I attached the other vertical 2x4. Then I added the other 1x6 boards that make the wall on the other side of the door. (I cut these with the circular saw.) Then I cut a length of 2x4 for the top of the door frame and screwed it in place. I repeated that step on the other side of the greenhouse.

8. Finishing the Front and Back Walls

The next step was to add more structure and stability to the greenhouse ends (front and back). In the picture you’ll notice “frames” above the side walls. These are made from 2x4’s and I measured, cut, and screwed them together before adding them to the greenhouse. There are four in total, and they are screwed to the door frame and to the 4x4 posts.

 

Notice how the cattle panels now have a nice arch. They are leaning nice and tight up against the side frames and the door frames.

greenhouse completed frame

Completed greenhouse door frames and front/back

greenhouse end wall frame

Frame, viewed from the inside

9. Adding the Overhead Beam

Finally, I added a 12 foot 2x4 overhead beam between the two doors for more structural stability. I used a steel rafter tie to attach it. (I had no idea what this was called so I described it to a store associate who took me right to it.) I'm short, so I did need another person's help to hoist this beam up there (and a ladder). 

greenhouse overhead beam

Overhead beam, attached to the door frames

greenhouse steel rafter tie

Steel rafter tie securing the beam to the door frame

THE GREENHOUSE FRAME IS DONE!

Remaining Steps: Hang the doors, anchor it, paint it, and cover it with greenhouse plastic.

10. Hanging the Greenhouse Doors

Shims and trigger clamps really helped in hanging the doors. I propped the door up with the shims and added some clamps on the side to hold it in place. I screwed in the hinges and the handle (that was satisfying!). I also added the hook and eye so I could latch the door. I wasn’t interested in the wind blowing my newly attached door around. In one of the pictures below, you'll notice that the bottom hinge is partly behind a 1x6 board. It was a minor problem I ended up with, so I just unscrewed that board to slide the hinge under it, and then screwed it back on as far as it would go. This is a good example of letting go of perfection as long as it still looks good and the door works.

greenhouse door hinge

Top hinge on greenhouse door

greenhouse bottom door hinge

Bottom hinge with one side behind a 1x6

greenhouse door handle

Handle and Hook & Eye Latch

greenhouse completed door

View of completed greenhouse door from the inside

11. Anchoring the Greenhouse with Rebar

The rebar was next. Since I built the greenhouse without a base or foundation, the rebar helps to anchor it to the ground in case of really high winds. It’s pretty heavy due to the wood and metal, and it’s unlikely to budge; but the rebar is good reinforcement and I don’t like to take chances. I used ½” rebar that was 2 ft long. Using a mallet I pounded it into the ground right up against the side walls. I tried to get them straight and in the ground about 10-12 inches. I got close ;). We'll just say it adds to the greenhouse charm. I attached the rebar to the side walls with pipe strapping. Note: Rebar is rusty and messy. You’ll want to take gloves with you when you buy it.

greenhouse rebar

Rebar, effective and almost straight; also, greenhouse charm

greenhouse rebar secured

Pipe strapping securing rebar to the wood

12. Painting the Greenhouse

Paint!! I loved this step. I used the color Nottingham Green by Benjamin Moore. I copied this color directly from the greenhouse that inspired me because I loved it so much. The greenhouse would look amazing in so many colors though: Periwinkle blue, Lemon yellow, Forest green…so many good choices. (How fun would it be to have several in all different colors?!) My friend came over for a painting party and I ordered food. We painted and chatted for a couple of hours. I did not sand the wood first. I think it really started looking like a cute greenhouse here.

13. Covering the Sharp Metal Ends of the Panels

Next was the easy step of adding foam pipe insulation to the ends of the cattle panels. Buy the ones that are already split down the middle and they’ll just slide right on. This keeps any sharp metal edges from puncturing the plastic.

greenhouse pipe insulation

Black foam pipe insulation on the cattle panel end

greenhouse pipe insulation

Black foam pipe insulation on the cattle panel end

14. Stapling on the Greenhouse Plastic

Greenhouse plastic!! The final step to getting it enclosed. I purchased a roll that was 24’x40’. It weighed 30 lbs. On a dry and calm (not windy) day I rolled the plastic out, and my partner helped me take the edge and lift it up over the panels to the ground on the other side. I made sure the plastic extended a couple of feet past the bottom of the greenhouse.  I started stapling the plastic to the top 1x6 board on one of the long 12’ sides, keeping it as smooth as possible. (Staple gun, staples.) I didn’t staple the plastic to the bottom two boards because the plastic will get rolled up during the summer to let air in. Once that side was done, I switched to the other 12’ side and stapled that one down, keeping the plastic pulled reasonably taut. The plastic was now secured and I could work on the ends. The ends were a bit like wrapping awkward presents and I just had to use my best judgement here. I wrapped the plastic around the corners, tucking and folding as needed to get it to lay flat. Spring clamps helped to temporarily hold the plastic while I stapled. Don’t be afraid to pull some staples/plastic up and re-staple if it’s not looking the way you want it to. I concentrated on making the highly visible areas look good, and then finagled the rest to make it work. This stapling took a while but it was so fun to see it all take shape.

Notes: This plastic is specifically made for greenhouses and is meant to last for four years. Many people have had it last longer. I intend to patch it as needed and keep it as long as I can. However, I do expect that I’ll have to tear it off and replace it at some point.

greenhouse corner plastic

The plastic is rolled and tucked to lay flat against
the side

greenhouse rolled up plastic

Closeup of the spring clamps that hold the plastic up during the summer

greenhouse end wall plastic

The front of the plastic is smooth and the extra is folded to the side

greenhouse rolled up plastic

Plastic is rolled up on all sides for airflow

15. The Finishing Touches

Within a few weeks it’s best to add 1x2 pine trim to the long sides and to a couple of areas on the front. This keeps the greenhouse plastic securely stapled to the wood when it gets windy. I didn’t do this the first year and the staples didn’t hold up to the winter winds. Some of the plastic ripped away from the wood and was really flapping in the wind; the trim would have prevented that. For winter, I cut a separate piece of plastic and stapled it to the doors; I remove it in the summer. To minimize air leaks around the doors in winter, I attached foam pipe to the 2x4 using outdoor mounting tape. I have a pretty finial that I haven’t added yet. I still hope to. Several months after I finished the greenhouse I added mulch all around the perimeter. I found that with the plastic being against the ground all winter and early spring, it became a muddy mess. Adding a layer of cardboard and then mulch keeps it much nicer and cleaner.

greenhouse trim

1x2 Trim on the front and side

greenhouse trim

1x2 Trim on the front and side

greenhouse pipe insulation in door gap

Foam pipe to block air gaps

greenhouse mulch

Mulch around the front and side

And there you have it! 

My greenhouse instructions for an afordable DIY backyard greenhouse for your garden. Although I have many hours into the structure, it was an easy greenhouse to build.

  

I've provided links to all the greenhouse materials that I used, but know that most can be found at your local hardware store, often at a cheaper price.

 

Connect with me on Instagram for current pictures or to ask me questions!

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