Looking for info on tall spindle trellis construction

I have looked a fair bit, and read about trellis failures. I have yet to find a recommended pipe size when using steel pipe for line posts.
Hubby is thinking 2 3/8" oil field pipe would be sufficient, and that would be every 30 feet. He is planning on putting 3 feet into the ground and using concrete in an 8 inch post hole. Terminal posts and anchoring system of course are important too.
Just wondering …does anyone has info or recommendations from personal experience?

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I am actively researching this too for a fruiting wall. I do not know of any one book that discusses this: unfortunately - in the Internet age - you have to wade through dozens of documents and copious forum posts to build a plan (and plan a build woot). Anyway, I found this which may start the laborious process:







30 feet is the standard recommendation for space between post. I normally see 4/5 inch CCA line posts with a solid brace with 6 inch post at the end of each row. I used deadmen set in concrete with high tensile wire for the end braces but I have also seen a standard fence brace used too.

I don’t have any experience with 2 3/8 inch pipe but when the hurricane hit with 60 MPH wind gusts it broke a 6 inch CCA end post this year. The brace wire held the trellis up but we just about lost the entire row which was loaded with fruit.


Tons of reading there. Thanks.

John Clements is great, check out his stuff on YouTube.

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If I constructed another trellis, I would focus more on the size of the end post and how deep they are. Also the configuration of the braces at the end of the rows.

After quite a few trellis failures in many parts of the country the designs have been beefed up a lot and one company offers a tool called Trellx to help with the design. Looks like the new recommendation is 6 inch minimum end post driven 4 feet deep in the ground which would require a at least a 14 foot post. My post hole digger only digs 3 feet deep which is what I used. I’m not aware of any standard post driver that will drive a 14 foot post.

Fortunately, my trellis failure from the hurricane winds was only partial and I did not loose the entire row like the orchard in the picture.

EDIT: I downloaded the TrellX tool and noticed it allows the user to choose between wood posts of several sizes and drill pipe in several sizes. Looks like the max spans are much shorter for drill pipe than for a 5 inch wood post. For example a 10 foot trellis in a 30 MPH wind will require 2 3/8 drill posts about every 10 feet in a 30 MPH wind compared to 19 feet for similar trellis with 5 inch wood posts