The trellis described below-
* supports the netting method described on the Bird Net page
* permits "tucking" (as opposed to tying) of at least 95% of
annual growth to maintain control.
The major characteristics of this trellising method are-
* canopy and fruit zone completely separated
* an elevated canopy (above your head) which is self managing
* pairs of non-moveable catch wires in the fruit zone
*designed for fruit-zone-only bird net protection.
The device on the top of the post is an Ingles Spreader (see topic page). Working from the top down, the canopy is 7.5 feet above ground, It is supported by 4" X 4" X 10' pressure treated posts with 6.5 feet above grade. The extra foot is obtained by the Ingles Spreader. There should be at least three wires to support the canopy. The center wire is necessary to distribute the canopy and prevent prevailing wind from forcing it to one side of the row. A single wire (#4) is 12" below the canopy and mounted on the top of each post. When the annual growth reaches wire #4, it is on its own for the rest of the season and there is no need to perform tying or management of the canopy.
The eight wires mounted in the post area are in pairs. The first pair, numbers 5 and 6 (pink tape in image) are spaced in holes drilled through the post to form a small (1.5") aperture. These are catch wires through which all shoots from annual growth pass. The reason for the small aperture is that this pair of wires also serves as "curtain wires" for mounting bird net curtains (see Bird Net). If you don't use this bird net method, the aperture could be larger with the wires mounted on the sides of the post.
The next pair of wires, numbers 7 and 8, (orange tape in image) are also catch wires, but are mounted on the sides of the post forming an aperture of 3.5 inches. All annual growth passes through this pair just to get it under control and headed toward the 1.5 inch aperture above. Wires 9 and 10 (orange tape) are also mounted on the sides of the post and these are cordon wires. Here you might be able to eliminate a wire by using a single cordon wire. I have a pair of cordon wires because some of my vines are trained to four short cordons instead of two longer ones. Also, this pair serves as catch wires for lower growth such as replacement canes.
Wires 11 and 12 (pink tape) are also 1.5 inch aperture bird net curtain wires and are only necessary if you use netting in the manner described on the in Bird Net page.
Again, the elevated canopy in these vine rows is well above the fruit zone and you don't have to wrestle with it during the season. If you want to kill Japanese Beetles, you need only one spray nozzle high enough to be aimed down at the canopy (the beetles start at the top and work down). If you want to spray for botrytis, one or two nozzles in the fruit zone will save a lot of expensive spray material. In other words, the economic and environmental rewards of separating canopy from fruit zone are significant and immediate.
Only the foliage in and around the fruiting zone shades the fruit. Leaf removal to increase sunlight is unnecessary in Maryland in a season of normal rainfall. However, removal of suckers shoots(also known as laterals) in the fruit zone is recommended to prevent unnecessary shading and crowding of the of shoots passing through the top curtain wires.
With the two pairs of catch wires (numbers 5, 6, 7 and 8) the human activity is pretty much confined to tucking annual growth between the wires. At least 95% of the annual growth does not require tying. Walking through the vineyard with no other tools than your hands will result in a well managed fruit zone.
You may use some discretion spacing the wires in the fruit zone. Your goal is to arrange the fruit zone in a 3 foot area (the distance between the cordon wires and top curtain wires). Keep in mind, however, that the fruit zone should begin about 40" above grade to facilitate easy picking.
Spraying the canopy is still essential, and all of the equipment we have seen will effectively treat a canopy 7.5 feet above grade or could be adapted to do so. The hobby grower with a back pack sprayer may have to get a longer wand, but the benefits of the high canopy far outweigh any inconvenience or expense associated with spraying.
At pruning time, removal of the canopy requires pruner elevation (in other words, unless you're very tall, you have to stand on something). We use a 16' tow behind plank walkway. A farm wagon that fits between the rows, could accommodate 2 to 4 pruners who could remove the canopy and clean the wires in two rows at the same time. Combine this with a tractor driver to creep the wagon ahead and the work goes very rapidly. Since canopy removal is a separate activity from the normal pruning, the canopy may be removed in late fall after leaf drop without fear of adverse impact on the vines.
The image on the right shows the 12 wire trellis full of annual growth. The shoots are about 98% tucked (not tied or clipped). This row is ready for netting.
Overall height to top of canopy (wires 1,2,3) 90"
Canopy wires 1,2,3,to top of post (wire 4) 78"
Top curtain wires (5 and 6) 68"
Catch wires (7 and 8) 56"
Cordon wires (9 and 10) 45"
Lower curtain wires (11 and 12) 31"
Questions? Let us hear from you.
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