Wherever grape vines grow, there must be a support system so they flourish and provide a bountiful harvest of delicious fruit. There are some important tips to keep in mind when building a simple, functional grapevine trellis that require research into the type of grapes you intend to grow. For instance, more often than not, grapevines need at least one or two other grape vines so they can grow on a trellis and encourage each other to grow. All it takes to build a grapevine trellis are a few sturdy materials and basic construction skills.
Research the variety of grapes you are going to grow to find the best site for your trellis. The trellis needs to be the correctly positioned for the type of sun and soil your grapevine needs (this varies between grapevine varieties). Determine whether you want 8- or 4-foot posts. Taller posts are best for warmer climates and shorter posts are best for places with cold winters.
With a shovel, dig a hole about 2 feet deep and insert the post. Pound it into the ground with the mallet. Layer some gravel or small rocks all the way around the posts in the hole for added support, about 2 inches thick. Backfill the soil into the hole until completely filled in, stamping it down tightly around the post. Keep main posts about 15 to 20 feet apart for each grapevine.
Insert the anchor posts into the ground next to the main post. Angle each anchor post away from the main post so it will be able to pull the heavy anchoring wire taut. Pound the anchor posts into the ground with the mallet. Secure the wire from the main post to the anchor by wrapping it one to two times around the top of the main post then pulling it to the anchor post, wrapping the wire around the top of it in the same manner. Since the wire is so heavy it will mold to the shape of the posts when you wrap it around, making it sturdy.
Leave about 1 inch between the wrapped wire and the top of the post. Pull the wire as tight as possible when securing it, than use the wire cutters to cut away the extra wire. For a two- to three-post trellis, an anchor post at either end is suitable. For a longer trellis, anchor posts should be at every stake.
Take the end of the extra wire, and wrap it around the bottom of the main post, about 3 inches above the ground. Run the wire along the length of the trellis, wrapping it around each post in the same manner as the main posts. This wire will act as a support system for the bottom of the grape vines trunk. Take another length of the wire 1 foot up from the top of the main post and run it along all the posts, wrapping it around each one and tightening it as much as possible. This wire will support the upper part of the grape vines.
Run pieces of the lighter catch wire right in between the two heavier wires, half way up the height of the posts. This will be to support the smaller vines that grow out from the main trunk of the grape vines, to train them to grow up and outward. It will also help make pruning easier, because it keeps all parts of the grape vine more organized for you to see dead, diseased or broken vines to cut back.
Plant the grapevines at the base of the wooden beams. Run the main trunk along the heavier wires.