Grape Trellis
Grape vines can grow and spread very quickly so it is necessary to construct a grape trellis the first year. A grape trellis will train the plant to grow upwards and give it support and structure as the vine climbs. There are two different methods by which to build this grape trellis. The first one utilizes one wire and the other uses two wires, also known as a double-curtain trellis.
First of all, you will need to get some posts made of pressure-treated wood. The space you will need for each vine is twenty feet long by six feet across. With either the one or two wire system, you should have two end posts, each of which is 7-8 feet high and 4 to 6 inches in diameter. In-between the end posts are the line posts. These can be 6 feet high but can be an inch less in diameter. The end posts should be put three feet into the ground with cross supports to stabilize them. The grape vines are going to put an enormous amount of weight onto the posts plus they have to be stable in all kinds of weather situations including high winds.
You will need wire and the attachments necessary to mount the wire on the end and line posts. The amount of fencing wire you will need is going to be approximately seven times the distance between the end posts. High tensile wire is the best choice, although the standard used in the past has been 9-11 gauge galvanized. In recent years, good quality metal end and line posts have been manufactured and are an alternative to wooden ones. They have not been tested over time to see how long they last before rusting.
It is important to construct the grape trellis the first year of planting. In the one wire system, the line should be five feet above the ground. In the two wire system (double curtain trellis), both lines are five feet above ground and four feet apart. This system allows for double the production space--forty feet instead of twenty feet. By the end of the first year the trunk of the grape vine should be fully established. Some grape plants may reach the top wire the first year but for most it is the second year.
The grape trellis system has many benefits, such as increased light for better photosynthesis and fruit production, disease management, easier pruning and harvesting. A proper trellis, trained and pruned grape vine will direct all of its energy into producing fruit. Your efforts in building the grape trellis will pay off many times over in the amount of fruit it will produce for wine, juice or jams.