A Cheap Homemade Trellis System For Tomatoes & Anything Else
What could the designer of the standard steel wire tomato cage have had in mind? Possibly ease of manufacture; certainly not real indeterminate tomato plants, with vines that can easily exceed six feet over the course of a summer.
After trying cages and considering a number of other trellis ideas, I decided to build something specifically designed for the way tomatoes actually grow. The “trellis system” would need to be: inexpensive; relatively easy to build; rugged enough to support any number of vines and fruit; and lightweight for ease of removal at the end of the season. It should be usable with other plants. And, most importantly, it should allow easy access to both vines and fruit.
There are two parts to it: the trellis part and the part that holds the trellis in place. For tomatoes the trellises are hung horizontally, allowing the vines to grow up through the squares. From my experience this summer, I’d recommend using three trellises held this way, (the photo shows only two trellises – I’ll know better next year) with the first hung about a foot off the ground and one foot between each additional one. For other vining plants a trellis can be held vertically.
The trellis is just a wooden frame that holds a lattice of galvanized steel wire. I made my frames 8 feet by 4 feet, but you can make them any size you want. To make the frame use either 2 by 2 inch lumber, or, if you have a table saw and want to save some money, rip 2 by 4 lumber into 2 by 2’s as I did. To make one 8 x 4 frame you’ll need two 8 foot long pieces, two 4 foot long pieces, and one piece a little shorter than 4 feet – measure this piece for length after the rest of the frame is assembled. So, the lumber needed for one trellis is one and three quarters of a 2 x 4.
Then, using a hand drill or drill press, drill holes at least 1/8 inch in diameter every foot over the length of each piece. To insure the holes line up, I find it easier to drill the first hole through the center of each piece and then each succeeding hole one foot to either side until the ends are reached. Drill through the thinner sides of each piece.
Assemble the frame by mitering the ends of each of the 8 foot and 4 foot long pieces, and then gluing the miters. The shorter center piece joins the two long pieces at the center of their lengths with a simple butt joint. Glue this also. It is important to use a good outdoor glue. I recommend Titebond 3. It is also essential to rigidly hold the pieces in place while the glue sets up (for about four hours). You can either nail the miters and butt joints together, as I did, or use clamps. Give the glue 24 hours to completely cure, as stringing the wire will put some stress on the joints. Round over any sharp edges with a rasp or router after the glue cures.
A word on the species of wood to use: I used simple pine. It’s cheap, and because I live in an arid region, I think it should hold up well provided the trellis is stored out of the weather off-season. But if you live in an area that gets significant rain, you may want to use more expensive cedar or redwood instead.
Now, to string the wire: The wire will be strung across both the length and width of the frame so that the wire lengths overlap to make one foot square squares. One trellis will need about 60 feet of wire. Use either 12 or 14 gauge galvanized steel wire. These typically come in 100-foot spools and sell for under $10.00 at hardware or home stores. 12-gauge wire, being thicker, is more rigid, but it also takes significantly more work to string. You’ll probably want to wear thick work gloves in any case. Start at the outside of the frame and thread the wire through a hole toward the inside (don’t forget the hole in the center piece!), continuing until you reach the hole at the other end of the frame. The wire should extend about 5 to 6 inches or so beyond the last hole to provide enough slack to tie a “knot” with. After you’ve tied the knot, go back to the other end, grab the wire, pull it as straight as you can without flexing the frame too much, give yourself another 6 inches or so, snip the wire with wire cutters, and tie another knot.
Do this for each set of holes. Then take a small snippet of wire (about 3 inches) and tie each intersection where the wires overlap. This may be tedious, but it will significantly improve the strength of the lattice. You may need two pairs of pliers to tie a nice tight knot.
Now pat yourself on the back and make two more trellises if you’re doing this for tomatoes.
The part that holds up the trellises is simply 8-foot lengths of 2 by 2’s either stuck firmly into the ground or attached to the outsides of a raised bed, along with some thick cord. I used ¼ inch braided nylon cord (this should last a few seasons before sunlight begins to degrade it). Use four such poles to hang an 8 by 4 trellis horizontally. For each trellis you hang, drill a hole through the top of each pole with a diameter just big enough to allow one end of the cord to be pushed through. Start the first set of holes about 4 inches below the very top of each pole. Separate additional holes by at least an inch. The idea is to form two loops of cord between the two sets of poles on which to lay one trellis (see photo). The trellis just lies on the loops – it isn’t necessary or desirable to tie the trellis. The height of the trellis can be adjusted by adjusting the length of the loops. You’ll probably need about 16 feet of cord for the lowest loops. I found it easiest to tie the two ends of the loops using simple overhand knots around pieces of 3/8 inch dowel – this makes it easier to undo the knots later on.
Ofcourse, if a trellis is to be used vertically you’ll probably want to tie the trellis to the poles.
2x4 x 8 foot lumber: Pine: $1.87 (Cedar: $4.97, Redwood: $8.27; 2x2 x 8 pine: $1.48)
14 gauge galvanized steel wire, 100-foot spool: $6.29
Titebond outdoors glue, 16 ounces: $7.97
Synthetic cord: prices vary widely depending on material.
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