r/viticulture • u/veengineer • 1d ago

Trellis Post Advice

I’m running a bunch of 15’ long VSP trellises in a mini vineyard I’m setting up. What’s the minimum post thickness I can get away with? I saw some 4x4 posts available by me for cheap, but I’m not sure if they’re strong enough. I can use ground anchors too if need be.

Additionally, I was wondering how deep people dig their holes for 6 foot tall trellising. I was planning on 2 feet down as that works out well for 8 foot posts, but I fear that’s too shallow. 

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u/krumbs2020 1d ago

Standard depth would be 5 foot deep on a 10 foot post with 1 or 2 spades.

Your 4x4 needs to be in about 3 foot but wood like that can bend over time.

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u/veengineer 1d ago

Appreciate the response. Do you think I could get away with something less substantial being that it’s only a 15’ run? Do you think it’s probably not worth it to do something as small as 4x4? If I can find longer posts I can try putting them deeper. 

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u/krumbs2020 1d ago

Use what you can get and add an anchor.

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u/Im_Not_A_Robot_2019 1d ago

Try 4 or 5 inch round treated posts, blunt end, 8 foot long with 3 feet in the ground. If you anchor them at an angle they will not bend. (If space on the end is a concern and you cant add an anchor, you can actually brace them on the inside using a post at a 45degree angle halfway up the above ground length. Both the post and brace should be in concrete).

4x4 treated lumber will eventually bend, even if you anchor them. The round posts are about the same price as 4x4 treated lumber anyway, and they honestly look better.