low tunnel construction

Grand Saline, TX(Zone 7b)

We're putting together some hoops for plastic (winter) and a light weight bug cloth for summer. These are long rows 90-100', hoops are 4'x 4'. My questions is for those who use them, how far apart do they need to be in order to prevent sagging or other problems.
Thanks in advance :0)

Deep South Coastal, TX(Zone 10a)

Our first ones were 9ft between hoops which sagged quite a bit with remay and plastic, but not shade cloth. Our second ones were 6ft between hoops and much better with remay and plastic covers. Our last ones were 5ft between hoops with no sagging at all. Our hoops are 4x4 also but rows are not as long as yours.
We are in a high wind area and the wind ripped the covers off the wider spaced hoops more often than the closer spaced ones. We use clips that fit over the hoops to hold the covers in place, plus weights on the bottom of remay or plastic covers.

Thumbnail by Calalily
Grand Saline, TX(Zone 7b)

Perfect, Thanks Calla!
Dh has been studying your photograph (looks fantastic, btw!) A few more questions if you don't mind :0)

Do ya'll anchor with rebar? If so what depth are they sunk into the soil and how much is above ground?
Are you using commercial clips, or something you made? We noticed you don't have them on every hoop. Any recommendations for how many clips we should use or order?

Deep South Coastal, TX(Zone 10a)

We use 2 ft rebar, hubby is outside so I can't ask him at the moment, but I think it was 3/8. This is driven into the ground 18 inches with 6 inches sticking out. We used either half inch or three quarter PVC schedule 40 in 10 ft sections for the hoops. These were pushed down over the rebar and into the soil as far as possible. The only time one has popped out was when it was hit with the bucket on the skid-steer. I'm pretty sure it was 1/2 inch PVC.
I bought the clips from Peaceful Valley, by the 100's. The wind catches the remay sometimes and flips the covering making the clips fall off, but we use more on the ends than on the sides.
I will be home in a week and can give you the item number if you need.

Madison, AL(Zone 7b)

Instead of anchoring with rebar, I used 18" sections of 1/2" PVC and drove them into the ground. The hoops are of 1/2" PVC and fit down into the "sockets".

I did sockets on all my beds even though I don't need hoops on all of them. So I can leave my sockets in the ground year round, and quickly pop up some hoops if needed.

Deep South Coastal, TX(Zone 10a)

Nicole, now did you connect the hoops to the sockets? Do you have rebar inside the sockets? We can remove the hoops from the rebar, but then the rebar is sticking up and I trip over it if I'm not paying attention. Ours are in use year round, but sometimes I don't really need hoops over that crop.

Grand Saline, TX(Zone 7b)

Thanks, this info should get us started in the right direction. My biggest concern was not having enough support when we really needed it, like right before a freeze or storm.
I found the Peaceful Valley clips and will order once we know the size of pvc we're using. We have enough rebar to get started and will start there, but Dh has considered wielding sockets from short lengths of conduit onto the rebar. I think we're going to wait and see how often we take these down or move them.

Madison, AL(Zone 7b)

I don't connect the hoops to the sockets, I just stick them down in the sockets a good 12" or so and they aren't going anywhere. The fit isn't completely snug, but the outward pressure is pretty strong.

It turns out the hoops are also useful for securing tomato cages and trellis' and stuff. I had originally conceived a plan where trellis' would also fit down in the sockets, but making trellis' out of PVC would just be too expensive (and too ugly).

Thumbnail by NicoleC
Deep South Coastal, TX(Zone 10a)

Nicole, I was just confused as both the sockets and hoops were 1/2 inch.

Madison, AL(Zone 7b)

Oops, typo. Sockets are 1" PVC.

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