How To Build a Garden Trellis
"This project sat in an inspiration folder on my desktop for a year and a half until the perfect opportunity presented itself."
Materials
This project was based on a photo I ran across on Instagram probably a year and a half ago. Since then it's just been sitting in an inspiration folder on my desktop. We generally get on a roll with projects and we’ll be picking projects for a certain event or something and inspiration just flows, and every so often it doesn’t. That’s when I bring that out and look to see what I have in there. It’s great, because there’s totally things like this that I love that sit in there for a long time, and then there’s the day that it fits, and we do it. That's what happened here! The 2017 Northwest Flower and Garden Show is coming up, which was a good excuse to make use of it.
It’s really basic, and I like this one because it looks like just a panel of a fence, even though it's actually a trellis. A trellis is a structure used to give structure to a plant that needs that structure. There’s the trellises that are used for holding up something like a tomato plant that gets top-heavy and can’t support its own weight, and then there are trellises that are used for growing a vine that you don't want attached to the side of your house. This trellis fits more into that category.
Step 1: Make Your Cuts
I used cedar for all of this because it’s really naturally pretty and it holds up really well outside. A lot of decks are made of cedar because it has a lot of natural anti-decaying properties. The one difference in cedar is clear- vs. tight-knot, but for this project it doesn’t matter which you use past aesthetic taste.
This is the 5/4" by 6" decking pieces. (They make up the slats of the trellis.)
- Cut the 5/4" x 6" boards into seven 30” pieces with a chop saw or circular saw.
- Cut a 30” piece out of each 2" x 3" (leaving a remaining 66” approximately).
Step 2: Sand
(If you don't have a ton of experience with sanding, pause here and take a look at the sanding guide we put together.)
Obviously you can get out an orbital sander and make this smooth and perfect, but the way I see it, the trellis going to be in your garden, and the main thing interacting with it is going to be a plant, and the plant doesn’t need it to be smooth and perfect. I used 100-grit sandpaper and just sanded out the big splinters that come on the end of the boards from cutting them.
Step 3: Measure
Lay out the 66” 2" x 3" pieces and, using a tape measure or a straight edge, find the halfway point of the board and make a mark. Turn your tape measure 90 degrees down the length of the board and draw a pencil line down the face of the board from that mark to indicate the center. Do this on the face ( the 3” side) of the board. This is the outside frame, so we’re going to be drilling through it into the ends of the slats, and the slats will be centered in the middle of the 2" x 3" so it’s a guideline for drilling later.
This is a good time to remember that even though it’s called a 2" x 3", it’s not ACTUALLY that exact dimension, so the center of the board isn’t exactly 1.5 inches. It’s actually a little more like 1 1/4 inches.
Step 4: Assemble the Trellis
Weirdly enough, assembling the trellis from top to bottom is actually the easiest way to construct it. When you’re fitting a bunch of pieces like this inside of two other pieces (like a frame), all the pieces have to be pretty precise and the same length, otherwise they won’t fit properly. Constructing it top to bottom—as opposed to building the frame and then putting the slats in—creates a little more wiggle room, because only one side is attached and being pulled in while the other side is more flexible. Also, because we’re trying to space the slats evenly apart, if you go from top to bottom you don’t have to worry about the spacing being perfect, because when you get to the bottom you just put the bottom slat on wherever it is. If you have the bottom slat on first, you’d have to worry about getting perfect spacing on all the other ones out in between. I try to avoid things like that!
Don’t be intimidated by the project, because it’s pretty forgiving. Remember, it's going to be covered by a plant! (Hopefully).
So: Starting with the top of the outside frame, position one 30” 2" x 3" piece on edge (resting on the 2” side) in between the ends of the two 66” 2" x 3" pieces (keep the pencil lines facing out). Secure with two four-inch screws on either end.
Step 5: Add Slats
Use a couple scrap pieces of 1" material (i.e. 1" x 2", 1" x 3", 1" x 4", etc) as a guide to attach the slats to frame.
If you have the scrap pieces laid out, it acts as a guide so you don’t have to clamp the pieces. They’re all just there and laid out. Which means this step went from being a total pain to being super easy.
Lay the scraps lengthwise inside of the frame and place the slats on top so that they’re positioned in the middle of the 2" x 3". Secure each slat with two screws on either end, drilling through the pencil line on the outside frame. The first slat should butt up against the top of the frame, and from there on space each slat ¾” apart. To keep the spacing even, you can use small 1"x scraps for this measurement—because it’s not actually 1"x! It’s technically ¾.
Step 6: Secure the Bottom
Fit in the bottom frame piece (2" x 3" x 30”) after the last slat is in place. This end should be snug against the slat. Secure with four-inch screws.
Step 7: Insert the Bor8 Impel Rods.
This is actually a really exciting part of this project for me because this is something I didn’t know about before doing this project. This is a preservative method to used to prevent the trellis from rotting that’s way easier than covering the whole trellis in something. Impel rods are tiny little rods with boric acid in them. All you have to do is drill a hole and put them in the wood, using a formula of so many rods for so many cubic feet of lumber. And as the boric acid in the rods interacts with water, it diffuses into the wood and helps prevent and stop decay, which means it’s something you can use on a new project like this or on a trellis in your yard that’s starting to fall apart.
With a 13/32” drill bit, drill two holes a couple inches apart at the bottom of either leg of the trellis. The holes should be 1 3/8” deep, and everything about this is very precise, so I measured and used a piece of tape on the drill bit to show me exactly where to stop drilling. You have to buy the right size of impel rods for the dimensions of lumber, and it will say on the package, this is for XX material. If you stil with the dimensions we did here, you have to get the rods that are for 2"x material. They’re all different sizes, so then you have to drill a hole that’s a 16th of an inch wider than the rod and an 8th of an inch longer, plus the size of the wood plug you’re putting in the whole afterwards to cover it. It’s a lot of very precise numbers. The rods we used a ⅓ inch wide by 1 inch long, which is really annoying because ⅓ inch is’t a real measurement! (Inches are are divided into quarters and eighths, and ⅓ inch isn’t divisible by any of those numbers!) And then you’re supposed to drill a hole that’s 1/16 of an inch more than ⅓ of an inch! This took a lot of calculations. It’s quite a process, but if you’re following this step-by step you don’t have to do the equation, because we’ve done it for you! Keep in mind that if you change the dimensions you’ll need to adjust.
With gloves on (you have to wear gloves because boric acid is not exactly human-friendly), insert the Bor8 Rods into the holes and cover them with a wood plug or putty so they stay put in the wood. Either is fine—whatever you have on hand or whatever you feel comfortable with. If one of those intimidates you, use the other one!
Step 8: Staining
(If this is your first timing staining, take a minute to review our tips on staining to get the best results on your project.)
I’m a sucker for dark stain colors, and particularly with this project, I think the design is really simple and elegant, and I think it lends itself really well to a darker color. It makes it look really sophisticated. But you could match it to your fence color, for instance, leave it as-is with the natural cedar color. The stain is totally optional.
A quick note: The stain we used here is nontoxic, so if you’re growing plants, it shouldn’t concern you. If it does concern you, now you an be un-concerned. Promise!
In my mind, the way this is designed there should only be a couple inches of leg you see above ground, which means there should be 16 inches or so below the soil. The hope is that you can just dig a hole, pack it down, and there will be enough support for it to stand up. Plants are pretty gentle; no one is leaning on it, so it should be fine. If you have especially soft soil or it’s not working that way, you can dig a hole and pour concrete. If that sounds intimidating or you don’t want concrete in your garden, you can use crushed gravel and pack it down around the base of the legs and that will provide support that the regular ground won’t.
There are a few times where you'll have to wrap your head around really tricky calculations, but overall this project is actually really simple! It’s partly because we barely sanded—I spent three minutes sanding, which is significantly less than usual—and then nothing was pre-drilled, so I only had to drill once. If you're looking for an easy way to prep your garden for spring (it's so close, I can feel it), I think you'll love making this trellis, too.
