It’s another edition of Weekend BuildsTM! In this episode we’re talking about building a raspberry trellis. Or is it raspberry trellises? Trellisi? Hard to say.
Anyways, we built a system to keep our raspberry plants from collapsing! This was a relatively simple process that only took a day or so to do. That is, if you order the correct number of wire vises (visi?) the first time around. We ordered half of what we required, so it technically took two weekends (don’t tell anyone).
The cedar raspberry trellis system is simple. Two 4”x4” posts put into the ground on either side of the raspberry bushes. On each post there are two cross beams, one near the top that is longer than the other located just under halfway up the post (think telephone pole style). Two wire vises on each cross beam and a bunch of wire and it is all done!
Before digging the holes and installing the 4”x4” posts, I needed to make dado cuts into each post for the cross beams. The dado cuts are 1½” deep, to allow for the 2”x4”s used as cross beams to sit flush. When making a dado cut on a long beam like the post, I use my miter saw. There is an adjustment that limits how far the blade comes down on each cut. I used scrap blocks of wood underneath the blade to set the adjustment at my desired height. When making dado cuts with a miter saw you need to add a sacrificial piece of wood along the miter saw fence. The extra space away from the fence makes the dado cut straight, rather than curved from the shape of the blade.
Once the four dados were cut, 2 in each post, I cut the cross beams to length using the miter saw. For our system, the lower beam is 2’ and the upper beam is 3’. This will make sense when the raspberries are tied up to the wire, but it allows for the natural shape of the raspberry bush. I also drilled a ⅝” hole on each end of the cross beams. The wire vises slot into these holes and are held in place with 1” wood screws.
Post installation time! This meant a lot of digging and some solid blisters. The soil at our house is very clay like. It makes for difficult digging, although it is great for keeping the posts in place after they are installed. Luckily for me, one of our neighbors had a post hole digger than I could borrow. I put my sunscreen on and got to work, digging 2 holes in line with each other, one on either side of the raspberry bushes. The holes are 3’ deep, allowing for 5’ of the 8’ posts to stand above ground. No cement necessary to hold these posts into place, since they aren’t holding much weight, they are a full 3’ into the soil, and our soil is clay like and basically becomes cement after we add water anyways.
I was so preoccupied with digging that I forgot to get a picture. Here’s a sample of what I looked like digging the hole.
Anyways, back to the raspberry trellis. After installing the posts I marked the center of the cross beams and lined them up with the center of the posts. I used 2½” wood screws through pre-drilled holes to attach the cross beams to the posts. Cedar is prone to splitting, so pre-drilling is a must. Pro tip – make sure the wire vises are facing the right way when installing the cross beams. It would have been really annoying to have to take off a beam and flip it over and reinstall it. But that also would be a pretty typical mistake of mine, just not this time!
Last step, add wire. The wire vises make this process extremely easy. One end of the wire is fed through the wire vise on one cross beam, and the other end of the wire goes into the matching vise on the other side of the raspberries. The wire can be pulled taught using pliers after it is installed through the vises. I recommend having someone hold the other post as you pull the wire tight, just to make sure it doesn’t twist or lean. For our trellis, we left the extra wire folded flat along the cross beams. Over time the wire will sag and leaving the extra wire gives us something to grab and tighten in the future.
Allyson tied the raspberry branches in place using twine and the new raspberry trellis was complete! Unfortunately, we did have two raspberry bushes get damaged by wind and grasshoppers this year, which is why there is a gap in our bushes. We’re hopeful the roots are still alive and they’ll produce next year (some small leaves are covered by chicken wire). If not, we may have to replace them in the future.