How to Build a Grape Trellis

How to build a grape trellis starts with your basic training plan. If you need a simple guide for what to do, I'm about to give you my proven step by step system..

Like the right site, the right training system makes a big difference. In my own vineyard, I use a simple two-wire system, with (mostly) cordon-trained vines. The cordons are trained on one wire, at about 5 feet high, with a second wire 15 inches above that. As the shoots grow up, they attach to the upper wire and are supported. If needed, I may tie shoots to be sure they don't break.

Although this will instruct you on how to build a grape trellis suitable for a small vineyard, there are a few effective different training systems that all work.

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Posts

Two types of support posts are needed for a vineyard: heavy posts that are the main supports of the wire, and lighter support stakes for each vine. The wire-support posts are generally made out of wood, while the vine supports may be wood or metal. Wooden posts, unless made of rot-resistant wood such as black locust, should be treated to prevent rot. Black locust posts can last as long or longer than treated posts and have the advantage of being free of chemicals that might leach into the soil.

The wire-support posts should be a minimum of 3 inches in diameter for rows up to 300 feet long. Larger diameter posts, up to about 6 inches in diameter, are needed for longer rows due to the increased weight of the wire and the greater pull on the posts. The number of wire support posts within the row varies with the type of system used. If a vineyard is exposed to a lot of wind, especially when the soil is wet, the heavy support posts may be set as close as 20 feet apart to keep the row from leaning.

Heavy wire-support posts should be set at least 2 feet deep in average soil. You will need posts at least 8 feet long in order to leave 6 feet above the ground for trellis use. In soft soils, such as sand, consider using taller posts and setting them deeper, or setting them in cement to anchor them well. In very rocky soil, posts can sometimes be set less deeply - say 11/2 feet deep for an 8 foot post. Rocky ground will hold posts more strongly than loam or other soft soils, though it takes more work to dig the post hole.

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Wire

The size wire generally used to support grapevines runs from 9 to 12 gauge with 9-gauge being the heaviest. If you go to a wire dealer, it is usually sold by weight rather than length; 100-pound rolls are the basic unit. The dealer may sell you smaller amounts, but you will pay a cutting charge for it. In some cases, the charge may be enough that it's cheaper to buy the whole roll. If you are a backyard grower galvanized steel may work for you. A short run of it won't stretch a lot and it's not that hard to retighten one or two small rows. Otherwise I recommend tempered, high tensile, stainless steel wire. It resists rust a lot better than galvanized and stretches so little you may find yourself replacing posts before you have to tighten wire.

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Wire Anchors

Wires must be stretched tightly to support grape vines. Simply tying wire to the end posts isn't sufficient. There must be some type of anchor, usually buried in the ground, at each end of the row, to which the wire is attached or the end posts must be solidly braced, to allow the wire to be stretched tightly. The easiest type to use is the commercial anchor. This is a heavy iron rod 2 to 3 feet long, with a loop at one end and a split disk at the other.

When setting the end posts of a row, if you plan to use wire anchors, set the posts at an angle of about 15 degrees off vertical pointing away from the row. This braces the posts against the pull of the tightened wire.

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Attaching the Wires

I didn't develop a really good method of attaching the wires until cordless rechargeable drills came along. These drills allowed me to drill 5/8-inch holes through the main posts at any height I wanted so that I could thread the wires through the posts, all the way down the row.

To attach the wire, I first drill two holes in the end posts at the appropriate height. The hole should be parallel to the direction in which the wires are to run. Then I drill another hole above those two at a 90-degree angle to them, and parallel to the ground. You should be able to look through the two lower holes and see the next post in the row, while the view through the top hole will be of the neighboring row. The top hole is for the anchor.

Run wire through the hole in the top and down through the loop in the anchor. Do this twice so you have two strands through the hole. Pull up the slack and leave at least a foot or more overlapping in each direction. Twist the ends around and over each other and wrap them thoroughly. Nothing else needs to be done at this point. Repeat this at the other end of the row.

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Stretching Wire

Take an end from the coil of wire and thread it through the lowest hole in the end post. Continue feeding out wire and threading it through posts all the way down the row. At the far end, thread the wire through the hole in the other end post, wrap it around the post at least twice, and wrap at least 1 foot of it around itself just back of the point where it enters the hole. The simplest option for a small scale vineyard is to pull up most of the slack y hand, estimating how much wire should extend through the hole to wrap around the post twice and leave at least a foot to wind back over the trellis wire, as at the other end.

With the majority of the slack pulled out by hand, hook the wire in the claw of a claw hammer right where it comes through the hole. With the head of the hammer braced against the post, rock the tool to one side to pull the wire tighter. Have a second hammer to catch the wire right at the hole, and repeat. By "rocking" it this way, you can stretch the wire quite tightly. Bend the wire around the post as you stretch, and it will resist pulling back it will resist pulling back enough so that you can wrap the wire all the way around the post to hold it, and finally wrap the wire around to fix it in place.

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Supporting Vines

Small posts are needed to support both the vine and the wire in the basic trellising system I've described. In my vineyard I prefer using steel fence posts to support individual vines. Further information on how to build a grape trellis can be found in "The Grape Grower" by Lon J Rombough.

This is an abbreviated excerpt from "The Grape Grower" reproduced with permission from the author Lon J Rombough. For more detail including diagrams you can purchase your copy from Amazon.com.

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