my hoop house made of 1/2" conduit

[wally mcgee]

I have a good time with this structure. I don't know how I got along without it. It has added a whole new dimension to my gardening. I would encourage anyone with the room for one to go for it. It is especially fun to work in while it is raining out...or snowing.

[SIP Gro-Tubs]

Originally Posted by wally mcgee

I have a good time with this structure. I don't know how I got along without it. It has added a whole new dimension to my gardening. I would encourage anyone with the room for one to go for it. It is especially fun to work in while it is raining out...or snowing.

What are the dimensions of the structure?

What did you do for the transition pc's from the sidewall to the arched roof?

Did you do roll up walls?

Terry Layman

[imp]

Enjoying your time is always good.

[wally mcgee]

This structure is about 9' x 31' and covers 2 of my garden beds. I used conduit connectors between the uprights and the arches. The bottom frame is made of 2 x 6 with holes drilled every 4' to receive the legs. As of right now my sides don't roll up. In my neck of the woods I prefer to keep the bugs and critters out. The ends are screened. I do plan to put auto vents lower middle of each side. It has stood up to some very strong storms.

[Wi-sunflower]

As nice as it looks, I'm afraid it isn't going to survive a snowy winter if you leave the plastic on over winter. The 1/2 inch conduit isn't strong enough, especially at 4 ft centers.

I've had several homemade greenhouses using 1 inch conduit on 3 ft centers eventually come down in part from heavy wet snow and winds perpendicular to the sides. Last fall I built a PVC "high tunnel" that I thought would make it thru the winter. But I made a couple of mistakes AND just about ALL the snow we got this last winter was near the freezing point and mixed with rain so was VERY heavy. It was flat as a pancake after the first storm.

I should be able to salvage most of the parts of that one and do a better job next time.

Don't let my experiences discourage you tho as I too enjoy working in my greenhouse especially in late winter before anything can be done outside. Just know you may need to adjust or modify it some to get thru the winter.

Carol

[wally mcgee]

This green house has been through a winter. By the way, I wrote my description above from memory, which is not what it used to be The ribs actually are 3' on center, and there are X bracing in the ceiling. The ends are 2 x 4 framing. It is a very sturdy structure.....I am a contractor.

This is my second hoop house; the first one, a prototype was only 12' long and I used it for 2 years until I decided to build this one. I actually re-used the arches in the newer model.

I have the plastic on tight, secured with wiggle wire.

In addition to the X braces I incorporated a bar over each bed, fastened to the arches, that run the entire width of the structure.

[wally mcgee]

You can see the X braces and the strut supports in the ceiling. They are very important to the integrity of the structure.

[wally mcgee]

Another thing I think I should clarify is that I used metal conduit, not pvc. 1/2" metal conduit is very strong.
Please forgive me, I'm rather new to this sort of thing.

[SIP Gro-Tubs]

Originally Posted by Wi-sunflower

As nice as it looks, I'm afraid it isn't going to survive a snowy winter if you leave the plastic on over winter. The 1/2 inch conduit isn't strong enough, especially at 4 ft centers.

I've had several homemade greenhouses using 1 inch conduit on 3 ft centers eventually come down in part from heavy wet snow and winds perpendicular to the sides. Last fall I built a PVC "high tunnel" that I thought would make it thru the winter. But I made a couple of mistakes AND just about ALL the snow we got this last winter was near the freezing point and mixed with rain so was VERY heavy. It was flat as a pancake after the first storm.

I should be able to salvage most of the parts of that one and do a better job next time.

Don't let my experiences discourage you tho as I too enjoy working in my greenhouse especially in late winter before anything can be done outside. Just know you may need to adjust or modify it some to get thru the winter.

Carol

To make 1/2" conduit stronger, get a 3/8" rebar and slide it down the length. Next fill the void around the rebar with expandable foam.

On your 1" conduit, don't try a piece of rebar more than 5/8" since it will be hard to bend to make the bow. Then fill in with expandable foam.

NOTE: Before filling with foam inside a bowed conduit, make sure its bowed to what radius you will be using to build the greenhouse.

4' canters are OK for Snow Loads, but to make it even better do a double layer plastic on top. Install a 60 - 120 CFM Squirrel cage blower before installing the 2 layer of plastic. Once the fan is on, the 2 layers of plastic will form a pillow on top of the greenhouse.

Depending how deep the center of the pillow is at the center will also help snow roll off without sticking. The heater in the greenhouse will keep the air warm between the layers, thus also help in melting any snow that stays.

Another item that you need to install which will help with winds hitting the sidewalls is to install 45 degree braces from your sidewall supports to your bows.

Here in south TX. the winter storms come out of NW, the spring weather usually comes out of SE. If you are wanting less windloads on the sidewalls, orientate the greenhouse so the ends are facing the oncoming direction of the winds.

Another thing to remember about snow accumlation that the pitch of the roof plays a big part whether snow will build up or slide off, even if wet. Local building codes will tell you what those pitchs are for your area.

Terry Layman

[wally mcgee]

What kind of foam would you use? The insulation in a spray can? Sounds like a great idea.
I don't even have electricity to this one yet. I started off just overwintering spinach and winter greens and each year I try something new. Last year tomatoes and cucumbers up twine. They did very well, but it has been a learning experience. I would love to take the next step and get elect.. for heat..etc.
I started with Eliot Coleman's idea with no heat etc but I would love to have lettuce all winter and get a bigger head start in spring.

Thanks for your input.

[SIP Gro-Tubs]

Originally Posted by wally mcgee

What kind of foam would you use? The insulation in a spray can? Sounds like a great idea.
I don't even have electricity to this one yet. I started off just overwintering spinach and winter greens and each year I try something new. Last year tomatoes and cucumbers up twine. They did very well, but it has been a learning experience. I would love to take the next step and get elect.. for heat..etc.
I started with Eliot Coleman's idea with no heat etc but I would love to have lettuce all winter and get a bigger head start in spring.

Thanks for your input.

Plain old foam for insulation, it will run itself down the tubes interior, but drill some weep holes to get better penetarion on long pc's.

Terry

[Wi-sunflower]

I'm glad it's really only 3 ft centers. And those cross braces are great. If they were in the first post I didn't notice them.

My early greenhouses were with metal conduit and they actually did last for quite a few years til an ugly wet snow with high wind collapsed part of 1 even with a double layer of plastic and inflated but without heat at the time.

My PVC high tunnel had a couple of design errors on my part but it was partly due to trying to make it cover existing rows of plants so they would last into winter. I think I will be able to make it work when I re-do it this fall. Not quite so wide and with more and better bracing.

Carol

[dpurdy]

wally mcgee,
I think you did a good job with your hoop house. I have a couple that I grow in. Regardless of how many braces or doubling your plastic, you'll have to be diligent about removing snow and not letting it pile up on top or along the bottom sides of your house. A broom with an extension handle will help you to remove excess snow during winter storms. You roof design should shed the snow fairly well. Hopefully, you can post some pics in December of your winter greens growing in the hoop house. What kind of temps are you recording inside your hoop house during warmer sunny days? Without being able to raise and lower the sides, I think you will have to address this issue as the summer temps increase. Tunnels get very warm and can exceed a 100 degrees without air circulation. You may want to think about a way to be able to open up the sides during warmer weather. Having both ends open will help but won't stop temps from reaching the 90's. I'm sure that you will find a way address this problem when it confronts you. You have good enough skills to build your hoop house, I'm sure that you'll find a way to add extra air movement and keep the temperature down to an acceptable level for your plants to flourish. Good luck with this endeavor, I wouldn't want to garden without my hoop houses. They provide me with a longer season and enable me to protect and harvest many more vegetables than I could in an open garden.
dpurdy

[wally mcgee]

I am considering adding wiggle wire about 2' up on both sides, and screening the bottom. I assume I could attach the screen with wiggle wire? I seem to have had a lot less trouble with bugs, etc. since I screened the ends in.