Building a hop trellis - questions

[bjhbrew]

I'm finally getting around to building a trellis in my backyard so that I can grow some hops in the ground instead of the containers Ive been using the past few years. I purchased some really nice 4X4 cedar post that are 14' long with the intention of spacing two posts 12' apart connected at the top with a cable. I've already dug one hole at a depth of 3 1/2' but may try to get that down to 4'. In the past I've set fence posts in concrete but I'm reading about how that may actually accelerate rot. So, hop growers of HBT what has worked for you? Concrete? Expanding foam? back fill with dirt? Also curious if you think that a 12' wide trellis will allow for 4 plants. I'd be happy to throw up some pictures once I get some progress going.

 

[GoeHaarden]

I purchased some really nice 4X4 cedar post that are 14' long

Wow! What did you pay for those in todays market? Wood is crazy expensive right now.

If you don't plan on using concrete and are just going to back fill and tamp, then I think the rule of thumb is to bury 20-30% of the post. That said, that is usually for a fence post and not a 14' - 4x4. To be safe I would use concrete. Cedar naturally prevents rot, but you could always seal the ends you plan to bury before you set them.

 

[bjhbrew]

Oh yeah, the price of building material is bananas right now! I'm fortunate that I have a connection at a local sawmill and was able to purchase them at more of a wholesale cost. Still expensive but probably half or less of what they'd cost at a big box store.

I think I am going to use concrete - my hesitation is reading about how it may actually hold the moisture in and cause premature rot. Also, having dug out some huge concrete blobs last summer to replace old rotted fence posts I can honestly say I never want to do that again! What I'm reading is that if using concrete I should make sure the concrete extends slightly above the soil level and the slopes away from post to prevent soil contact and pooling water; seems pretty sound to me.

 

[Brewin’&Qin’]

Not sure if they would hold a 14’ tall post, but I have seen brackets that get set into the concrete and the post bolt into the bracket. When you set the concrete you would do the same as you indicated. Set above the soil line and after setting the bracket in the concrete slope the concrete away from the bracket to keep water from pooling. As mentioned, I have seen it used for deck building where there are additional support added to the post, not sure how 14’ up on its own would work, although I guess the trellis would add a bit more support to each post.

 

[willy_mugobeer]

Couple suggestions ... 1) You might angle the posts outward by 20 degrees or so ... so while the bases of the posts are 12' apart, the tops are about 16' apart. This will help prevent sagging in the middle, as you can tension up the wire or rope on top without exerting (as much) inward force on the main posts. 2) Maybe add a couple 2x4s (like maybe 4 feet long?) as "T" tops on top of both the posts; that will give you space (depth) to run two main ropes/wires across the top from the ends of the 2x4s, and drop double the amount of twine leaders down to the plants.

(I say this having constructed something pretty similar in my neighbor's yard ~5 years ago out of discarded fence poles, set in a concrete base. Really wish we'd angled them outward; there's no way to prevent the sag in the middle, so what should be up at 11-12 feet, is usually more like 9-10.)

Just my humble opinion but four plants seems like a lot for that tight of a space. I think you'd get better results with two or three.

 

[bjhbrew]

I wish I could angle the posts out, that makes total sense. The truth is I’m trying to make a space work that’s pretty tight, there’s not a lot of areas in my yard that will get adequate sun. The garden bed I’m planting in is right in front of a fence that runs east-west on the south side of the yard. The little plants won’t get much sun when they’re down low but my hope is they will grow to a height where they are no longer shaded by the fence. I ended up digging the 2 holes 14’ apart and went a full 4’ down. I’ll likely join the tops of the posts with a 2x4 or something to prevent sagging. Not really sure how much hop plants will weigh.

 

[bjhbrew]

Oh and I’ll concrete them in but I ordered some sleeves that get heat shrunk on that are supposed to prevent the rot that occurs right at the soil line. I’ll post some pictures when I eventually get the posts in the ground.

 

[apache_brew]

When I set 8' 4"x4" fence posts in concrete, I like to dig the hole an extra 6" deeper and toss gravel in the bottom first, and then set the un-sealed wood post bottom two inches below the top of gravel. From there pour in mixed concrete above the soil like and taper off like you mentioned. The next day apply a sealant to the seam between the post and the concrete like this Sikaflex 10.1 oz. Construction Sealant White-7116045 - The Home Depot

With this application, maybe give it some more thought and consider if another connection method would be more appropriate for long term protection. MPBZ Not saying these are what you need, but maybe they are? The 7.25" contact height doesn't seem like it would support the potential 14' height of a post, but maybe 10'? Check for yourself. I just prefer the idea of not encasing the post in concrete and eliminating trapping moisture.

 

[rlmiller10]

to give you more height you could go with a more shallow depth for the posts but then bring the cable across the top and down to a ground anchor. Slanting the posts slightly out would help as well. I would go with this even if the base of the posts had to be moved a bit closer. I think on a 4x4 you will get the tops leaning in or bending in with time.

 

[NitrogenWidget]

I was going to go with Pressure treated 16' 4x4's then saw the price.
I'm now going with 16' 2x6's ripped down the middle and nailed together. half the cost.
My harbor freight auger will go a little over 2 1/2 ft with the 4" diameter attachment.
I put rocks or gravel in the bottom then pour dry cement in around it and sprinkle with the hose.
then i use my hands to grade the top of the cement away from the post so any water runs away from it.
I did that 20yrs ago with my fence posts and they are still solid.

I'm going to have 4 posts total.
My new trellis will be roughly 20x6 ft.
I plan to train the hops horizontally towards the sun once they reach the top (and they will).

I have 1/16" steel rope coming for the main supports and simple twine for the verticals so if it gets here by Sat i'll build everything.

edit: decided to just stick with 2 posts.