Building a Wire Fence for Grapevines

Posts

• The same posts that would be used for most farm fencing operations can be used for a grapevine support. Common wood posts include those 3 to 5 inches in diameter and 8 feet long. Steel posts are also used in grapevine supports. Setting wood posts commonly requires more labor than driving steel posts. Posts are spaced every 21 feet if vines are spaced 6 feet apart or 28 feet if the vines are 7 feet apart.

Anchors

• The weight of the wire and the grapevines puts a load on the wire. The wire will sag and posts will become crooked if the ends are not anchored. Brace assemblies similar to corner post assemblies used in livestock fencing can be used. These assemblies include two posts spaced about 5 feet apart with braces between them. This spreads the strain to both posts. Another option is an anchor, a long bolt with a helix end that bites into the ground as it is turned. A wire is attached to the eye bolt at the other end and then to the top of the end post. Keeping this wire tight provides support to end post and wires of the trellis. A short post, set an angle away from the end post, can also be used as a tie-back post. The wire from the tie-back post to the top of the end post supports the posts and wire.

Wire

• Smooth high-tensile wire is used for the horizontal portion of the trellis between the posts. The common wire size is 12.5 gauge although others are used. One or two wires are used horizontally depending on the grape variety and the method of trellising.

Keep it Tight

• Wire strainers are often attached at one end of the wires. These ratcheting devises pull the wire tight and remove the sag that can occur as the wires naturally stretch. A tension indicator spring is often included on the other end of the wire. The wire is attached to this spring. When the spring is partially compressed the wire is at the proper tension. The spring can then absorb the natural contractions and expansions of the wire as temperatures change.