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Oregoncp's 10x12 Harbor freight greenhouse adventures

Let me proceed this by saying I am a horrible forum poster. But I am going to give this a go, to chronicle my new 10x12HFGH.

I have wanted a greenhoing use for years (probably close to 12). I have always been held back by a lack of usable space to install a GH. About a week ago I finally closed on my first home. It is a great house for me and my family, and has a wonderful fenced in back yard. My wife says the only reason I really started looking at buying a house was because I wanted a greenhouse. I tell her she is crazy, but honestly it was a factor in the decision to commit to buying a house.

The next decision I had to make was what kind of greenhouse to go with. Cost was a bit of factor, having just bought the house I couldn't go to crazy without upsetting my wife. After looking at the options I narrowed it down to framing my own, or buying a harbor freight and beefing it up to the point that it would survive our Oregon coast storms. In the end I decided on the HFGH for several reasons. First off was looks. The place area I had planned for the GH was in blatant view of my new neighbors bedroom window, and I didn't want to build some monstrosity right in front of them. Next was cost. Even with the extras needed to make the HF strong enough, it still came in cheaper than building a similar sized wood house and covering it with something other than poly film.

To start with my goal is to get the GH up and operating to the point I can grow highland neps in it fairly simply. After that I will refine everything and build a Lowland chamber inside. Eventually I plan on using Arduino to automate pretty much everything.

I am basing my build off This blog. It has so much good info and tips on making the HFGH work.

Progress so far:

First thing I had to do was build a level base to build off of. I was going to dig down to get everything level, but decided I didn't really want to dig down 6+ inches to match the low spot. So I went off the high corner and just elevated the base from that point. I dug down 36" and set 4x4 PT post in concrete. Each hole has almost 160 pounds of concrete in them. I used some 6 inch screws to build the base and secure it to the posts. The 2x3 boards set diagonally are just to keep everything square while I set the posts. Soon I will get some cedar and finish the outside down to the ground level, and fill the inside with pea gravel.

After the PT base is set, the greenhouse base goes down. This is just a metal C channel that comes in several pieces. I put it all together and got it square on the base before using deck screws to secure it down. One tip I have for anyone building this GH is about the corner brackets. The instructions show the bracket on the inside of the C channel. I found it fit much better on the outside.

From this point I am just going to post my pictures. IF you have questions, ask away

At this point I added one of the extra things mentioned in the blog to help sturdy everything up. I used 3/4 emt to put a brace from side to side to prevent the walls from pulling apart. I only did two of them at this point because I want to get my lowland room built inside and the EMT will interfere with that.

Next I wanted to get my benches started because I am attaching them to the frame from the outside. The benches will add a ton of support for the entire GH. The bench process just sorta happened as I went. I knew what I wanted, and I just cut and dado'd around stuff as I went. The bench looks high right now, but the floor will be about 4" higher when i am done. This puts the top of the bench at 42", and leaves me room to do a lower bench and have room for stuff under that on the ground.

It got dark, so I stopped outside and went back to taping the edges of the poly panels with metal sided duct tape. I am doing this to help prevent moisture and mold inside the panels. Crossing my finger that it works.

Thats where I am for tonight. I am hoping my 25 rolls of weather stripping show up tomorrow so I can start installing panels after I finish my benches.
More to come and I progress.
Gaaaah jelly! I have the 6x8... With multiple people, I still had a hard time getting it assembled. I can't even imagine how annoying the 10x12 one was to assemble!

Just a tip... you should caulk the panels in or use foil tape to tape it up on the inside. My 6x8 leaked really badly until I taped it up with foil tape on the inside where the panels met the frame (only on the top and bottom of the panel). After I did that to both sides of the roof, my greenhouse is 100% (maybe 99% lol) leak free and it holds heat well into the evening. It used to cool off within 15 minutes to the outside air temperature. It also holds moisture a lot better too.

This should be really cool! I wish I had gotten the 10x12 because with just 35-40 Nepenthes my greenhouse is completely packed... :(
very nice build OCP. Congrats!
Gosh! My dream greenhouse.


Good growing,
very cool.. looking forward to seeing the finished product.
Well I'm really jealous! Congrats! I WANT ONE!
Haven't had a ton of time to do stuff the last couple days, but I did get a few things done. Namely the framing for the lowland room inside. I still haven't decided on what material I am going to use to cover this room, but I am leaning towards poly film on each side of the framing for now. I think the double layer seperated by the wood framing will help keep the heat in fairly well.

The diagonal braces I did on the walls add a HUGE amount of rigidness to the whole structure. I am now fully confident that this greenhouse will stand up to any weather the coast can throw at it.

I decided to put the doors together and get them hung. Alot of people complain about getting the doors to hang and operate correctly. I spent about a hour adjusting them, and they now slide real nice. They still have a small gap between them on the bottom when closed, but when I put some extra weather stripping between them and they are clamped shut the gap will be sealed up real well.

I also got the 1/2" hardware mesh mounted on the bench I built.
I bought 25 rolls of weather stripping off ebay. I am really hoping that shows up today so I can get all the panels in and actually start using the greenhouse.
I love this thread! looking good!
  • #10
My weather stripping showed up today. Not the best day to be putting up greenhouse panels. The wind was gusting 15-20ish mph. But being that I am a pretty impatient person, I pushed ahead.

I tried to work panel by panel so nothing was left loose at all.
First was applying the weather stripping all the way around the frame of each panel.

After that shove the panels in, and apply the supplied clips. The instructions for these clips are total crap, so it took me a few minutes of messing with them to figure out how they are supposed to sit. After figuring them out, they are actually pretty handy. They clip in fast and actually get a pretty good bite on the panels. Most guides I have read recommend ordering a extra set of clips so you can double up on most panels. I didn't do this, but I now plan on getting some more headed my way. (also be careful installing these. If you get one half in and slip while pressing the other half in, they can shoot off into oblivion, or into your eyeball.)

With just the clips installed the panels still have the potential to blow out, especially in the winds we get here at the coast. So I ordered a bunch of stainless screws and stainless neoprene bonded washers to add to each panel. I screwed these through the panel and into the diagonal braces. I used 1 washer outside, and another inside as a spacer to keep the panels from flexing inwards to terribly much. In my opinion this is a absolutely needed addition to this greenhouse if you are building it anywhere that gets winds in excess of 15mph. Not only does it keep the panels in, it adds even more points that the whole greenhouse is tied together, adding rigidity to the whole structure.

Tomorrow I will be able to get the rest of the panels up and have a working greenhouse.

I moved my neps from the window sill in my old house straight out the the bench in the unfinished greenhouse. My N.x "Lady pauline" is FEASTING on the ants.

  • #11
moving right along..
You should take a vacation and come put one of these together for me.
  • #12
Very nice greenhouse!
  • #13
'Looks great! Certainly makes me drool seeing what you have done with it. :drool:
  • #14
I got busy and never updated this. I got the rest of the panels on, and put my meager collection inside.

Next up, when I can get a little more cash. Installing a RO unit, with a 100 gallons or so of water storage. A pump and misting system. And before winter comes, I plan on running a 50amp feeder out so I can run a heater and such. And getting more plants!
  • #15
If your pea gravel is deep enough, you may want to see about installing a dripper hose underneath hooked up to a timer, it's a great way to keep the humidity up.
  • #16
The gravel is 3 1/2 to 5 inches thick. (deeper in the back corner) I have been spraying it down when the temps start to go up. It seems to help keep the temp down a little and the RH up. I had a lot of plans for temp/RH control. But being on unemployment for a few weeks due to work being slow has put a dent in my "play" fund.
  • #17
A hose and a timer should only run about $35, it basically sprays the gravel down for you, but only put it under where you won't be walking on it. What are the temps hitting now?
  • #18
I will look into finding the stuff to get some water dripping under the gravel. I have a couple old holey hoses, maybe I will just add a few more intentionally placed holes and get a timer setup. I actually have the moeny to set up my ro/mister system, I am just being "responsible" and holding onto it, till I get past this slow work period. Knowing me, I will just get impatient and order it next week though :p

Its been unusually warm here recently. With the vents open and a fan going inside, I can keep the high around 95. Thats about 10 degrees higher than I would like for the max temp. I am pretty sure with a RO mister I shouldn't have any issues keeping where I want. Another thing on my need list is some shade cloth. That should help me quite a bit also.
  • #19
looks good man.. I'm jealous.
  • #20
A drip hose is around $5-10 for a 50' one from home depot, careful with the hole poking because then you end up with a sprinkler hose which sprays everything in sight and not just the gravel (I made that mistake when they were out of dripper hoses at the store). On the shade cloth, I just had a custom made one done from farmtek for the same greenhouse, came to $130, was actually cheaper than buying their ready made sizes for some reason, I had mine made to cover the full sides though so you might not need something that large.