I checked out trellises at my local hardware and garden stores, and was shocked to find that even basic wooden ones cost at least $30. Forget what you'd pay for a fancy wrought-iron one! The one I made cost about $6 in materials, and took me less than an hour to make. I used five 8' 1x2s, a hand saw, a drill and a handful of 1.5" screws. If you have any scraps of 1x2 around, this is a great opportunity to use them up, since this project requires some shorter pieces, and it doesn't really matter how long they are. Here's my setup:
I started by laying an 8' 1x2 that would be the center piece on the ground, and attached a short (about 1') cross piece to it about 18" from the bottom using two screws. If you want to be sure that the wood won't split, you can pre-drill the holes, but I just went ahead with the screws themselves and backed up and drilled if the wood looked like it was starting to split.
I then attached two more 8' 1x2s, one to each end of the cross piece, using only one screw each so that I would be able to adjust the angle between each of them and the cross piece. This is how you control how much wider your trellis is at the top than it is at the bottom. I just sort of looked at it and adjusted it until it seemed right.
I used a scrap piece of 12 that I had lying around for the next cross piece, attaching it where the vertical pieces were the same distance apart as it was long. I then cut one of the other 8' 1x2s into two pieces, one smaller and one bigger, and attached them lower down and higher up on the trellis, respectively. I attached each one to the center piece and each of the other vertical pieces with two screws.
I used a scrap piece of 12 that I had lying around for the next cross piece, attaching it where the vertical pieces were the same distance apart as it was long. I then cut one of the other 8' 1x2s into two pieces, one smaller and one bigger, and attached them lower down and higher up on the trellis, respectively. I attached each one to the center piece and each of the other vertical pieces with two screws.
At that point I decided that the trellis had enough bars and vertical pieces for my purposes, but you could certainly add as many cross pieces as you want. If your outside vertical pieces were farther apart, or you wanted to build a very tall trellis (or a short wide one), you could add more vertical pieces. I would recommend attaching them to the second or third cross piece, so that more structure is added to the trellis as it gets wider.
Here's how the trellis looks now that the grape vines have grown a bit more, and are used to being supported by it.
Grapes are, of course, far from the only type of plant that a trellis like this could be used for. It would be great for roses too, and you could use different sizes and widths of trellises for raspberries, cucumbers, pole beans or any kind of climbing vine.
You could also paint or decorate this trellis in any number of ways (red, anyone?) to add a splash of extra colour and interest to your yard or garden. Do you have a home made or decorated trellis? I'd love to see what you've done, and hear your ideas for how I should jazz mine up a bit!