Home » Blog » Harbor Freight 10×12 Greenhouse

Harbor Freight 10×12 Greenhouse

Harbor Freight 10×12 Greenhouse Construction

Starting Your Own Greenhouse – Home Grown Veggies:

With today’s high gas prices comes high food prices, but that’s not the only problem. Challenging economic conditions can introduce problems in the quality of foods and produce that we consume.
First was the spinach scare, then lettuce, now tomatoes. Fed up, we decide to build an inexpensive harbor freight 10×12 greenhouse to grow all our summertime vegetables; canning any excess for winter consumption.

Greenhouse Construction:

The first step was to  find adequate space. Next was to design the greenhouse shed itself. Finally we would attach a manufactured greenhouse. The idea being that attaching it to a building would add structural strength.

We did a search on the web and found greenhouse prices running several thousand dollars. That cost could make the price of home grown veggies a loosing proposition. Searching further we found one MIC model of greenhouse made by  Harbor Freight, The HFGH 10×12 model 93358 for a mere $599. The price has now jumped to $789. Luckily we managed to get in on an early season sale. If 10 x 12 is too big, try the HFGH 8  x 10 model 93920 for $499.

Google can help you find many good sites that will help you build and modify the Harbor Freight greenhouse. These models seem to have become a DIY cult item for gardeners on a budget.

Here is a link to one blog that shares seven time saving steps in building your HFGH.
It’s a great addition to the sketchy factory provided instructions and is a RECOMMENDED READ.

Progress of our DIY Garden Shed and 10×12 Harbor Freight Greenhouse project.

Garage Shed Foundation – May 30 2008

garden shed foundatin photo

Garden Shed Foundation

Construction begins with town approval and building permit.
Excavation and foundation framing, gravel and re-bar took about 2 hours.
Photo at left shows the 12’x24′ garden shed foundation.
Excavating and concrete was done work by local contractor.
Cost for the concrete slab, about $1800.
Concrete poured and sealed the next day.

Garden shed construction progresses…

garden shed construction progress

Construction in progress

The gravel pile on the south end will eventually become the greenhouse foundation.
The south door will be the entrance for greenhouse.
Framing on the ground is a 4×6 pressure treated timber foundation.
The greenhouse base will be locked in gravel and the framing secured to the shed’s south wall.
As of 3/2014, we’ve had no storm damage (knock on wood).

The garden shed gets a roof.

Garden Shed Getting a Roof

Garden Shed Roofing

After just under 30 days of construction, the garden shed is finally taking shape!
Contracted the scary labor out to a local roofing firm.
Cost of labor: about $250, and they were done in 2 hours.
Any price to keep me off the roof.


Secure the Greenhouse to something solid.


Garden Shed and Greenhouse

The only way to ensure this model will stay standing for year to come is to attach it to another solid building. The greenhouse is shown attached to the south side of the garden shed. The total cost of the shed and greenhouse including concrete work. Roofing and all materials were just under $5000.


June 25 2008: Here is the final project result.

completed Harbor Freight 10x12 Greenhouse project

Completed Green House Exterior

The greenhouse is in operation with plenty of growing space. The structure rides out storms very well. This last weekend saw 50 mph winds and hail. No problems whatsoever. This photo also shows how the roof pitch of the greenhouse compares to a standard 6/12 pitch of the shed. It looks better if the two roof pitches match or are at least close. Looks like 7/12 or 8/12 would match well.

Completing the interior with shelving

greenhouse interior shelving

Completed Greenhouse Interior

The inside of the greenhouse features a heavy duty shelving structure made from 4×4 AC2 treated lumber stained a redwood color. The color of the raw lumber was not very appealing and the stain job was worth the effort. Be sure to stain BEFORE the poly carbonate panels are installed or they will become spattered with stain. There is about 32 feet of 32″ wide shelves and the upper support will be for future wire shelving. Do not use lumber shelves above or they will cut out a considerable amount of light.

Safe, Bug Free Veggies:

We can now grow our own vegetables in a controlled, bug free environment that should accelerate production and be a fun hobby for years to come. The next step is to add some basic automation for watering using and Allen Bradley Pico controller and a few relays and dishwasher water solenoids to feed a Misty Mate 17 nozzle patio cooler. We’ll keep you posted as this develops… Have Fun!

Misty Mate Kits of Plant Watering

How Well is It Holding Up?

Follow up: I have been occasionally losing panels during high wind storms. Luckily we have a fully fenced in yard and the panels have always been contained by the fence. For those who have lost panels, I can get 6mm replacement poly carbonate sheeting locally in DePere Wisconsin from the exactly same place Sundance supply gets their poly. I am a dealer for this material. Leave a comment if interested.

Update: As of July 26 2013, my green house is still standing and working great. The panels are slightly yellowed after 5 years of exposure, but it’s mainly from dust and dirt.
The Misty Mate irrigating approach did not work out so well. Our well water has too much dissolved solids that block the spray nozzles. The best approach is to use a small diameter soaker hose instead. Oh, and to keep panels from flying off, I reinforced them with silicone around the perimeter and center, plus added a few extra screws & washers.

Update: May 7 2015 – The green house is still standing a performing well after seven years. No major yellowing other than the accumulation of dirt and a few bugs and leaves. 7 years later and HF is still making this greenhouse: http://www.harborfreight.com/10-ft-x-12-ft-greenhouse-with-4-vents-93358.html buy one, you won’t be disappointed.

Update: June 27 2016 – Even after a rough spring and early summer with many severe storms, no damage at all. However, since I spray a lot of water inside, the base steel appears to be rusting away. Not sure what that will do to the stability, but is doesn’t seem to be going anywhere. I am already planning on what to do in case it does finally fall apart, but until then, we’re still good to go.

If this thing ever does fail, I’ll likely re-use the panels and build a cedar or MicroPro treated wood framed structure, or buy a new one.
This model appears to have a 10 to 12 year lifespan. I suspect a highr price might reflex better quality and longer lasting parts. For the initial price, it was well worth it.

Here are some comparable greenhouse kits available on Amazon:

This article was originally posted on barplan.com

The Final Straw

On April 15th 2018, the Green Bay area received winter storm Evelyn, (or should I say SPRING storm) a storm of the century magnitude ice storm followed by a blizzard dumping up to 29 inches of snow in the area. Here we got about 18′ of wet heavy snow and ice. It proved too much for the aging Harbor Freight Greenhouse to take and it broke her weak back.


collapsed greenhouse

snow load collapses greenhouse

Weak Back?

I say weak because from day one, the kit contained the wrong roof ridge sections and I patched them together with some scrap aluminum. Regardless, I think this storm would have taken out any light structures as it collapsed local hotel and warehouse roofs. She served us well for nearly a decade, enduring many high winds and snow loads; but Evelyn, who shattered records going back to 1905, was the final straw that broken the camel’s back.

Caught on Camera

Two weeks later, the thought came to me; did my security camera catch the collapse? Sure did! Here is the video clip. The collapse happened at 11:49am and 7 seconds. Enjoy.



By |2018-05-02T22:06:09+00:00July 1st, 2008|Wares|22 Comments

About the Author:


  1. Lissa Roberts November 2, 2009 at 8:38 pm

    I too have this greenhouse and have had problems with the clip system. I now need to replace some of these panels. They have been damaged by blowing out. Where do you get these and how much are they?

  2. Kathie Martinelli November 12, 2009 at 10:01 am

    I have two of these greenhouses. They are two years old and have been nothing but trouble. If you expect to keep the panels in, you will have to screw them down. There are some good web sites out there that tell you how to do that. Also, be aware that the Harbor Freight panels deteriorate very quickly. My roof panels are brittle and yellowing. I doubt if they have any UV protection at all. The panels are being advertised as being nearly indestructible. That is totally untrue. From what I hear, Harbor Freight is not standing behind the product. I don’t know this for a fact because I haven’t contacted them myself. If you replace panels, be sure to get good quality with a guaranteed life expectancy. I will have to replace many of my roof panels and will not be buying them from Harbor Freight. Everything they have is from China and there seems to be no quality control.

  3. Mark November 12, 2009 at 10:10 am

    I wouldn’t say nothing but trouble…you must consider the price and remember that any item sold at HF, is not the top of the line quality. I will agree that the panels can be a pain, but I’ve screwed them down with on center screw & nylon washer backed by a rubber o-ring and this greenhouse has withstood some very nasty wind storms. I live near DePere Wisconsin and there is a polycarbonate distributor here who sells a 6mm UV protected panel. I had set up a preliminary site at uvpoly.com but have received no inquiries.
    Bottom line is that the aluminum frame is nearly indestructible and the 4mm panels could be replaced quite easily with the 6mm variety.

    Oh, and about the made in China statement – I’ve got news: EVERYTHING is now made in China!

  4. roofer somerset November 27, 2009 at 11:08 am

    Oops was doing a google search for roofing and came across this post. Not exactly what I was searching for but much more interesting lol! Oh well, gotta get back to work…thanks, bp

  5. Charlie Hunter January 4, 2010 at 4:11 pm

    WE lost our 10×12 greenhouse with the last strong winds. I happened to be home and was watching it, but my last trip out to see if it was ok turned out to be the last time I saw it. It collapsed in the wind. I was abble to save 90+ percent of the panels but the metal frame work is a total loss. Would anyone like to purchase the plastic sheets?

  6. Mark January 4, 2010 at 5:25 pm

    Wow! – How strong were the winds and where do you live? I built my greenhouse with the north end attached to a garage, the east side blocked with large arbor vitae trees and the west side block by my house. We’ve had 60+ mph gusts and no problems.

  7. Kevin S January 4, 2010 at 10:52 pm

    Charlie – Very sorry to hear about your loss of the greenhouse. How fast were the gusts and was it in the open ? What a terrible shame, and all the work you put into it. JUST finished my 10×12 and must have spent over 150 hours building (and rebuilding) it. I’d heard about panel blow outs and have run a steel cable through most of the beams to at least keep them from getting away. I’d be interested in at least some of your panels as I’d like to build a vestibule / reinforcement between the GH and garage, and would like to have some replacements handy. Thanks.

  8. Jenny G January 29, 2010 at 2:03 pm

    I need to purchase at least one, preferably two roof panels. Please get back to me with price. I live in ventura, ca 93001

  9. Eldon Kimball March 25, 2010 at 10:18 am

    I am looking for some panels to replace mine which have gotten old and cloudy. I got these from Sundance originally so would be interested in buying same type.

  10. Diamond Tools August 18, 2010 at 12:35 am

    Good information and pretty thorough as well, do you mind if I reference back to it? I’m blogging about this too, and you have some good info I hadn’t seen before and I’d like to post a similar article. I look forward to reading follow ups and hope it stays updated.

    Diamond Blades & Tools

  11. Gary September 26, 2010 at 5:30 pm

    Hi: My HF Greenhouse is about four years old, and the panels are shot (yellowed, brittle, pitted, cracking). I would like to replace with 6mm. Please let me know what the pricing is on the panels you can supply. Thanks!

  12. Pete November 7, 2010 at 9:08 pm

    I too am looking for 6mm poly panels. Could you send me the info on a few panels.

  13. Lynne March 12, 2011 at 9:28 am

    Hi, I’ve inherited an old (70’s) metal framed greenhouse abt 8′ x 10′ in the backyard with many glass panels broken. It’s withstood years of heavy weather admirably and seems still sturdy. We considered tearing it down but I would rather repair it. Any suggestions?

  14. marty April 3, 2011 at 6:35 pm

    I am interested in some replacement 6mm panels. Please email me the specifics, thanks.

  15. admin0 May 15, 2011 at 9:36 am

    I am no longer selling panels due to the cost of shipping.

    Our Harbor Freight Green house is still doing fine. The panels are slightly dirty from dust and leaf debris but after 3 years, the panels still look great. It’s also endured many high wind storms and prolonged periods of strong (45mph+) winds.

  16. DWB November 1, 2011 at 7:10 am

    Looking for a replacement roller for the top of HFGH door. Nothing at local hardware stores or Home Depot or Lowe’s. Any suggestions where to find one?

  17. Patrick Ryan November 12, 2011 at 11:14 am

    I need some replacement glass for a greenhouse – some of the panels are curved others are not. I can sent pictures/sizes if needed. I’d like to get some pricing. The greenhouse is attached to my house and it would be nice to get it back in shape. (We just bought the house w/ it.)


  18. admin0 February 2, 2013 at 10:39 am

    2/1/2013 and our greenhouse is still doing great against the harsh elements of central Wisconsin. Still have all the original poly panels, turning a little yellow, but this is due to dirt getting inside the cells of the panel and leaf tannins that brew on the roof and drip down.

    I may be firing up the UVpoly.com site soon, so if you need panels, post the sizes you require.

  19. barkeep February 14, 2015 at 8:35 am

    February 2015 and the old HFGH is still intact, yet shut down for the winter. Panels are hanging in there, a little yellowed but mostly from dust and dirt.

  20. Dean March 28, 2018 at 1:31 pm

    I’m going into my 3rd year with my HF 93358 10×12 Greenhouse. I’m located in Colorado at 7300′ elevation. We get some pretty high winds, up too 70 mph, and some pretty heavy snowstorms (maxing up to 3′). The steep slope of the roof helps with the snow to a large degree.

    Other than building a more rigid base to attach it, we pretty much built it from the instructions with the following exceptions: We used soft Loctite on the screws and we installed some high quality automatic vent openers.

    The first big problem within weeks of having it up, was the roof was bowing more than 10″ from snow load. The main support beam was bending at the joint in the middle. We went in and put a center support from the ground to that joint.

    And as many have said, we’ve had our share of panels taken out. Once one of the panels comes out, then its almost a domino affect. Our solution has been to put up a windbreak about 5′ high and about 12 feet away on the windward side.
    We’re also seeing hail damage where the hail has gone through the external surface. (I belive its because the panels have gotten some what brittle over time).
    I am seeing some of the yellowing in the panels now and looking at panels. The prices I get from Harbor freight range from about $13 to $15 for the side and roof panels. Other panel suppliers are much higher and you have to buy standard sheets and cut them. This leads to lots of wasted material.

    I’m looking to replace all my panels, especially wall and roof panels. I can list them, but I’d rather just refer you to the harbor freight model 93358. You can download there manual off the product page and there is a pretty decent parts list in the back of it with the dimensions of the panels.

  21. mlxmod March 30, 2018 at 10:16 pm

    My HF 10×12 is going on 10 years old. It’s still doing fine although last year I noticed the bottom steel frame is starting to rust out. I used 30 year clear silicone to secure the panels and a few extra screws and fiber washer to hold the panels in. Mine is attached the south side of my garden garage so north and south winds have not effect on the structure. The east is blocked by large arbor vitae trees and the west is pretty much blocked by the house. This is probably why it’s lasted to long. Panels look good, but yellowed a bit from dirt and sun, but not brittle yet. Gonna run it till it falls apart, which may take some time yet.

  22. mlxmod April 17, 2018 at 8:09 am

    Here I thought winter was over, but Mother Nature had a surprise in the form of snowstorm Evelyn. Dumping 18 inches of wet heavy snow on the roof finally collapsed the structure. I will rebuild using lumber and used windows from the local re-store. I already have one 4’x4′ double pane window that was junk picked last fall. I knew this day would come. 10 years is not a bad lifetime for a $500 greenhouse, especially in northern Wisconsin. CAD drawings coming soon.

Leave A Comment