Harbor Freight Greenhouse Construction

[dragoneggs]

I have wondered about using the corrugated fibre glass panels for roofing. They are fairly clear and would be pretty strong compared top flat panels. Next time I go into HD I will make a point of checking them out for price. I figured these could be used for a greenhouse and probably be much stronger and reasonably priced with framing etc.

Yes but depending on your greenhouse frame, you might have some real issues fitting them. If you are designing from scratch they might work. One feature of greenhouse panels is they are double walled, giving you some insulating value. Not much probably in the grand scheme though.

 

[dragoneggs]

Now that all 4 auto-opening roof vents are installed I have moved on to the plumbing. I did have to reinforce the mounting cross piece as the provided bracket did not have a nice resting place. This was accomplished using a simple aluminum L section that I adhesive bonded to the green house frame. See photos for before/after. You will notice how much the original bracket was twisting during the opening of the vent. A much cooler day today outside so the greenhouse temp is only 75degF so no opening to check the beefed up design.

 

[dragoneggs]

The plumbing starts with a 3/4in riser and a ball shut off valve. Just above that I installed a faucet and then 'T'd off for a timer and drip system. The 3/4in supply and brass fittings is overkill but it is sturdy and looks good IMO. I ran the poly tubing along the lower third stiffeners across the back and along both 'long' sides of the greenhouse. This will allow tapping into the pressurized line anywhere along the three sides. I also capped off the supply just above the T for future expansion for hanging plants and/or a mist system.

 

[Bob77064]

dragoneggs, great job.

 

[dragoneggs]

dragoneggs, great job.

Thank you Bob... this evening I spent some time on the electrical. I hopefully will post some pics of my progress tomorrow.

 

[dragoneggs]

I finished up the first bench for the greenhouse. Bench is 10ft long by 30in deep by 36in tall. I welded up some thin wall steel square tubing, painted it with truck bed-liner spray, and built a top out of 5/4in tight knot cedar decking material. I decided to section it into three removable pieces to add some versatility to the design. Still need to come up with the rest of the furniture/shelving, etc. designs. Looking for ideas... feel free to chime in.

 

[dragoneggs]

Rainy, cool day here so the greenhouse is getting another good 'leak' test. Roof is doing well except for one small drip at one of the four roof vents. Since they are not gasketed/sealed when closed, I am actually surprised I don't get more than an occasional drip. But around the base where the frame is attached to the 4x6 PT foundation, I do get leaks, especially at splices and in one corner where it is coming in almost steady from roof and gutter drain off. These aren't all that concerning but I think when it dries out, I will shoot some silicone caulking in the seams and splices.

 

[dragoneggs]

I finished wiring one of two 20amp circuits. I used the grey PVC conduit and waterproof boxes to route it along the upper horizontal wall braces. I didn't have much to grab onto other than these 1/2 by 3/4in tube stringers, so I cut a few pieces of aircraft grade aluminum sheet that I had laying around to make a mounting plate for the boxes, screwed them into the plate and adhesively bonded the plate to the wall brace. Not rock solid sturdy as it will flex and move with the wall but plenty stiff for plugging in a electrical cord. The green color on the plates is aircraft primer. I left a little of the plate hanging below the brace to allow room for a label to I.D. the various wires. Now if anyone can tell me how to pull the pin on the hinges without breaking it... I will reorient the dang covers to swing up instead of sideways. I tried a punch but a couple of persuasive blows didn't budge it.



The first outlet is GFI mounted on the back wall, then 2 more outlet boxes are on the long (side) wall giving me a total of six receptacles on this circuit. The wife uses heating mats for seed germination. This will make it very convenient to plug them in as the outlets are located above the bench. Oh, and excuse the tie wraps supporting the PVC conduit... I need to fabricate a few clips to tie into the T bolts that secure the horizontal braces.



I have another 20amp circuit still to wire but not sure how I will employ that. Thinking of an outdoor motion light near the entrance door and probably a vent fan with louvers on the back wall. I am pretty sure when the weather warms up, the auto opening roof vents won't move enough air to keep the greenhouse from getting too hot!

 

[troutsqueezer]

As far as leaks go - it never occurred to me to try and stop any from coming in from the rain because when I am in there, I am a wild man with the hose, watering everything in sight and pretty much soaking much of the interior on a regular basis.

To mitigate heat buildup, an interior-hung shade cloth sure does help.

 

[dragoneggs]

As far as leaks go - it never occurred to me to try and stop any from coming in from the rain because when I am in there, I am a wild man with the hose, watering everything in sight and pretty much soaking much of the interior on a regular basis.

To mitigate heat buildup, an interior-hung shade cloth sure does help.

Yeah the leaking around the base is no big deal... but I am a bit of a perfectionist whether it shows or not. I never thought I would say this, living in the cool PNW, but I now can see some kind of shade cloth would be a good mod. I am now pondering how I could make one that is easy to deploy and roll up maybe with some kind of crank or pull cord system??? This greenhouse thing is getting a bit obsessive for me... AND loving it! (As Maxwell Smart used to say).

Kind a 'cool' to see the weather break a bit here as the gray clouds and rain broke and watch the roof vents go into action automatically with the sun beating down. It doesn't take long for it to heat up significantly but sun was short lived. The sun was only out for 45min and the cool rain is beginning again... oh well. Actually now turning to pretty hard or wet rain as we say around here :laughing:

 

[troutsqueezer]

For the interior shade cloth, I ran three pieces of PVC on the inside; one at the top, suspended from the ridge and one on top of each of the two side walls. I draped the cloth over the top PVC, fastened it with a couple more cable ties and draped each hanging piece over the side PVC's. If I want, I can drape both sides of the cloth over just one of the sidewall PVC pipes so that full light enters thru one or the other half of the roof. Or I can roll both sides up and tie them to the center PVC but I've never had to do that. I cut slits in the cloth so I can access the vent handles.

 

[dragoneggs]

Power on! Night shot...

 

[corl]

Your total build looks great! When I made tables for my little greenhouse I used two levels. I calculated the angle of the sun at my latitude and place them so trays on the lower level would get sun too. The space under the lower shelf is for storage since I use all available space on the tables for trays. I can get 33 flats into my greenhouse. I really just use mine for growing bedding plants but it paid for itself after two years. Its a bit more sturdy than the HF greenhouse but that is described in the posts. New Greenhouse Nunamaker Farms - Nunamaker Farms in West Grove, Pennsylvania - Home

 

[4shorts]

Power on! Night shot...

View attachment 371548

That just looks so well done. If you had that around here you'd have families living in it :laughing:

I wouldn't expect anything less from you. That's a super job. :thumbsup:

 

[dragoneggs]

That just looks so well done. If you had that around here you'd have families living in it :laughing:

I wouldn't expect anything less from you. That's a super job. :thumbsup:

Thanks Paul! Yeah some of the detail is a bit of overkill but you know how perfectionists are! Here is a day shot with some diffused evening sun. Note the auto vent openers doing their job even though it is only 60degF outside. It is a nice sauna! We are thinking of adding a couple of plastic chairs and a few overhead misters and we will have a tropical paradise right here in the cool NW. :cool2:



Now I better do a little landscaping around it so it isn't an eye sore.

 

[dragoneggs]

Your total build looks great! When I made tables for my little greenhouse I used two levels. I calculated the angle of the sun at my latitude and place them so trays on the lower level would get sun too. The space under the lower shelf is for storage since I use all available space on the tables for trays. I can get 33 flats into my greenhouse. I really just use mine for growing bedding plants but it paid for itself after two years. Its a bit more sturdy than the HF greenhouse but that is described in the posts. New Greenhouse Nunamaker Farms - Nunamaker Farms in West Grove, Pennsylvania - Home

Hi Corl... thanks for the compliment. I checked out the thread you posted on your greenhouse but unfortunately the pictures didn't seem to be there. Sounds like you have a very nice operation going!

 

[dragoneggs]

An update and a couple of 'action' pics.

The Univents are working great! We had an 80degF day today here in PNW!!! Near record temps I think. Vents are opening and closing wonderfully. Starts are sprouting and I installed a misting system on a rod that I can raise/lower and it is on an auto timer. I left them for 4 days and all is well so the goal of automation is working! I do think I will need a powered/louvered fan for the summer heat though.

 

[wngsprd]

Thanks for the update. I've really been amazed at what you've accomplished. Maybe I'll give it a try after I complete some other projects that sit top on my list.

 

[dragoneggs]

Thanks for the update. I've really been amazed at what you've accomplished. Maybe I'll give it a try after I complete some other projects that sit top on my list.

Thank for the compliment... I will be glad to answer any questions in detail regarding adding strength and stiffness to the HF structure and also the plumbing/electrical. I have a ways to go to completely outfit it but figured I would add or modify as we populate with plants. Looking now to add a wash/rinse basin with drain and a dedicated potting area that captures spilled potting soil for easy recycling.

 

[troutsqueezer]

... and a dedicated potting area that captures spilled potting soil for easy recycling.