How To Build Your Own Greenhouse from Carport – Part 1

Why build a greenhouse?

Greenhouse in winter

Because 5 inches of snow in the middle of May. That’s why.

Best answer, the winner.

You may be asking “why spend the effort to build a greenhouse? Why not just buy one?” Because, of course, they’re expensive, right?

And I didn’t have the funds to buy one. So if I wanted to have a greenhouse, it needed to be built by me, and easy on the wallet.

Therefore I got a Harbor Freight (HF) carport frame that was missing the cover, gratis! I already had plans to make a greenhouse, so this worked out great.

Note: This post may contain affiliate links that give us a small commission at no cost to you. See the Disclosures page for more info.

Also, if you like getting free tools, sign up for the tool giveaway in the sidebar. Matt from The Tool Merchants gives away free stuff. Pretty awesome!

More answers!

The second question related to the above why build a greenhouse is what good is a greenhouse?

Answer 0.25: Because desert.

You know what they say? “It’s a dry heat.” Oh yeah, that makes it all better! Too bad it’s still 105 degrees!


It’s dry. Really dry. We get around 9-10 inches of rain a year, split mostly into April/May and Sept/Oct.

See the pic above? Sand is great on a beach, but when you’re many miles from the nearest body of water, not so much.

Greenhouses help keep the humidity up, so it’s easier to grow plants. Big plus!

Answer 0.5: They hook you with the samples…

At a previous house, I built a small 4-foot square “greenhouse” that barely qualifies. But it gave us daily green salads for months, starting in mid-March and continued until summer when the lettuce and spinach bolted.

It tasted amazing, and you hardly needed dressing at all, so I would graze every time I went to the garden, sometimes adding peas or leftover winter carrots and onions.

It wasn’t pretty, but if enough people want to see that project, I may add a post later and link it here.

Answer 1: SAD mitigation

We live in a climate that is cold and snowy during the winter. Sunlight exposure is limited.

If you have even been hit by Season Affective Disorder (SAD, such an apropos acronym), having the ability to enter a warm, plant-filled paradise and rest in a hammock would certainly lift your spirits.

We start hungering for fresh greens and growing things as soon as they disappear in fall. And that feeling intensifies as the winter drags on.

Eventually I find myself rubbing my face (like a cat) into fresh herbs from the grocery store. Yep, I’ve got it bad!

Answer 2: (Cat) Security

The layout of our non-permaculture-designed house does not lend itself to either storage (no coat or linens closet? REALLY?) or seed starting.

So we needed a secure (read: not accessible to cats) place to pot up plants and start seeds. A greenhouse was perfect.

Answer 3: Two words. Aqua. Ponics.

Yep, aquaponics (which shall henceforth be known as AP in TPL-speak. See the glossary).

It’s a healthy multifunctional connected system with fish, plants, water, and bacteria.

Note: A great resource is The image below is from their site. - What is aquaponics? – What is aquaponics?

So (also) at a previous house, I set up a small AP system, consisting of a dozen pet store “feeder” goldfish/minnows in a small water trough, pea gravel in a bus tub, a small aquarium water pump and some tomato suckers.

It worked surprisingly well considering my lack of experience and cobbled-together setup.

This time, though, it will be different. In-ground fish tank, piped to overhead strawberry tubes, crisscrossing towers of lettuce, running down to beds of various veggies, and maybe even a tropical tree(!!!) or three if I can keep it warm. Yeah baby! Mangoes!

So there ya go: 3.75 answers for one question!

Design decision and size…

My carport was 10×17 feet, so that’s the rough size of the greenhouse as well.

I also really wanted to make a walipini (earth-sheltered greenhouse from South America), but I determined that our latitude and shallow ground would not be the best for that.

So beggars not being choosers, I had the frame and wood, so I made lemonade while the sun was shining. Or something like that…

It also is covered in film on the north and south sides. I had considered only putting film on the south side and creating the north wall with plywood or siding, but the budget struck again.

Per square foot, plastic was cheaper. More on this later, if you’re interested, in the costs section.

Now on to the steps!

  • Get materials
    • Carport frame
    • 2x4s & corner cushions
    • Greenhouse film
  • Assemble carport frame & locate/orient it
  • Attach 2×4 wood to tubing frame
  • Frame out ends
  • Plumb & level
  • Install braces
  • Attach corner cushions
  • Make door
  • Attach film
  • Enjoy it

Huh, a 12-step program. Well that explains some things…

Step 1. Get unused/unwanted carport frame.

I got mine free from a family member who had the wind rip up the cover, and now is useless as a carport. But very useful as a greenhouse frame.

Just FYI, the poor welding and construction is pretty sad, but we have a fix/mitigation for that!

Step 2. Get 2x4s or some kinda wood.

But what do you mean you don’t have a project pile of wood you can grab from? (@fellas: tell your wife I said being a packrat is OK!)

You’re going to have to remedy that if you want to stick around here!

Kidding, just kidding. (But seriously. Why not? How you get projects done is beyond me!?)

I used the wood to lay against the end tubing frames, as well as to run along the outline of the greenhouse.

Plus I used some extra, because if you have scrap or reclaimed wood like me, some are bent/broken or warped beyond using.

To avoid making this one big mega-post and burning out your eyeballs, I’m breaking it up into a series.

This post series is continued in Part 2.

If you’d like to know more ways to live better, we’ve partnered with Claire Goodall to offer the Everyday Roots ebook. It’s over 350 pages of home remedies, natural beauty recipes, and DIY household products.

This ebook shows you how to protect yourself and your family from toxic products and use healthier, all-natural alternatives. For more info Click Here or on the pictures!

OK, that’s all for now folks! Do you have any questions or comments about greenhouses? Ask your question down below and let’s talk! You can also use the contact form, or email me at info at thepermaculture dot life.

Thanks from TPL

P.S. If you’re looking for a cost-effective quality greenhouse you don’t have to cobble together, there’s a solution.

Bootstrap Farmer has greenhouses that are the lowest price per square foot online, including shipping!

They also have lots of greenhouse and farming accessories. Check out their Greenhouse Kits.


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