Does anyone out there have any advice on building a trellis for a very short raspberry row? Two of them ~15 feet long, to be exact? And I'm especially hoping to hear from those who share my dislike for the look of that orangey type of pressure-treated lumber. Pictures would be great! I was hoping instead to use those 8' long, 3" diameter round posts that are green in color (b/c they're outdoor treated wood, right?) with Wirevises to string the 12-gauge wire. I was planning on cementing them into their already dug 3-foot deep holes, but someone at work told me that cementing would actually rot the posts faster AND that the tension from the wirevises would eventually pull the tops of the posts toward each other. Is that true? Comments? Is it just me, or is this WAY more complicated than it seems like it should be? I've read the Fine Gardening article by Darlene White and they live somewhere West of the Cascades. Anyhow, lets hear your opinions!
Not to worry, you are off to a good start. Those posts that you have can be stained any colour. Setting them in concrete works for most of us, just remember to cone up the wet cement mix to make a run off from the post & hole. A cross beam of 2x2" at knee level and a wider cross beam , 3-4' near the top will enclose the future growing canes. You are in for a decade of berrys.
Thanks for the encouragement, Dunc. So the green, round posts can be stained, too? Good to know, though I kind of like the green. It's the orange that I'm not fond of. So how can I attach crossbars to round posts? Could I perhaps cut a post in 1.5' lengths and attach them with a rebar-core after drilling a pilot hole? Sort of like a peg-and-plug thing? Might be hard to cut an exact fit for that...wonder what tool would be best for that? I might have to post pics of whatever I come up with. Stay tuned.
If you're going to use cross beams/bars, cut a dado into the post on the outside side of the post so you have a flat surface to attach to. The tighter you pull the wires, the tighter the crossbar is pulled against the post. I would use 1 1/2" metal square tubing or angle iron for strength, and attach to the post with lag screws. I would attach the wire to threaded eyebolts in to the angle iron/square tubing that could be adjusted to keep the wire taut, otherwise it will eventually stretch and sag.
Not being a woodworking type, I looked up the meaning of a Dado joint and found a glossary of joinery definitions. I'm wondering if I could use a mortise and tenon joint? I'd like to try to achieve the look of a uniform double-cross that is made entirely out of wood. I am thinking I could drill-press a dado the exact circumference of the cross arm (3-4") into the side of the vertical post, then drill a pilot hole through the center of the dado in the vertical post and into the center of each side of the crossarms, then drive a piece of metal rebar into that hole to use as a tenon? Or will that not be a strong enough connection. I can see why people don't use round posts to attach crossarms! Still, it WOULD look cool...I just don't know if it will hold up or be worth it.
I would just cut a dado slot into the outside of the post that matches the thickness of the crossbeam. Obviously you want a flat surface to attach to so the dado would be deepest in the middle and tapering at both ends. The wood cross bar should fit nice and snug. I would use lag bolts to attach the cross bar into the post, and still use eyebolts for attaching the wire. For the cross beam you should use a hardwood so it won't eventually bend and break.
Applying the KISS rule....flatten the bit of the pole against which the cross-piece rests so it doesn't wobble side-to-side. Use a chisel, freehand with a power saw, hand saw, whatever. It doesn't have to be a work of art. tension the wires equally on either side. You may want to include turnbuckles. One of the nice things about gardens is that we all do these things with varying degrees of competence, patience, artistry & imagination. Some of my arrangements are pretty idiosyncratic & funky! It's the plants that are the goal after-all.
Thanks for the reminder, Lysichiton! Right you are I believe. I'll post some pictures when I'm done with this little project.
It's pretty easy to cut a dado vs flattening the back side of the pole. Just use a handsaw and cut two parallel lines equal depth in the pole the width of the crossbeam. Take a wood chisel and chip out the waste so you have a flat bottom and you are done. That way the crossbeam is supported in the dado top and bottom and with the flat bottom of the dado resists twisting in all directions. Threaded eyebolts or turn buckles provide tautness adjustment for the wire. Of course there are many ways to skin a cat...You could buy square posts instead... Actually re-reading the first post I see that the posts are 3" diameter which is pretty small. I would go minimum 4" square or larger. The 3" won"t last very long. I based my directions on a 6" round pole. If you cut much into the 3" it wouldn't last very long.
Sounds like whatever you build will put my raspberry row to shame :) If you pull the wires very tight, you probably should brace your posts. I've been using laundry line, which hasn't pulled the posts over, but also isn't pulled all that tight (so needs snugging up every couple years). You might throw a shovel of concrete into the hole before putting in the post so it's not exposed to the dirt on the bottom. No way I believe concrete rots them out faster than just burying them in dirt!
