VITICULTURE NOTE 2: INITIAL VINEYARD DECISIONS

You have selected the site, you have chosen what to plant and have decided who you are going to sell grapes to. Now what?

Surely it's time to plant grapes. But what about layout, plant spacing and trellis decisions? For a new grower the task may seem daunting. Conflicting and sometimes outright bad advice abounds to further confuse things. I am going to try and clear the fog by offering a highly simplified step by step plan of attack which should get you started. I, as always, encourage you to research other sources as well for other expert opinion.

1. Decide what kind of grower you want to be. Do you have the time, financial resources and dedication to be at the top in quality? Is your site up to it, or would you be better off concentrating on what I call production viticulture. Be honest here. If you aspire to be at the top of the quality pyramid then be prepared to spend extra for a narrow tractor, trellis supplies, plants and ultimately more for cultural expenses. If you choose to be a bulk supplier then your focus should be on minimizing the cost of new equipment and minimizing establishment costs while getting your vineyard quickly into cost-effective production.

2. Decide on your trellis type. In my opinion, for novices this is an easy decision. For quality-driven growers of vinifera and hybrids, a vertically shoot positioned (VSP) trellis is indicated. For cost-driven producers of hybrids and american varieties, I suggest implementing a single high wire (SHW) (upside-down) trellis. Note that I deliberately don't mention american varieties in the context of quality-driven viticulture nor do I mention vinifera in the context of generic producers. It's best to concentrate on the market segment in which you might be most successful. Whatever you do, try and avoid mixing trellis types.

3. Choose plant spacing. Yields and quality are higher with closer between-row spacing. Of course one must find a tractor of adequate performance which will fit down those rows. Minimum row width can be determined by adding thirty inches to tractor width in the case of VSP trellis and 36 inches in the case of the SHW. The bushiness inherent in SHW training requires more room. Specialized vineyard tractors are available which narrow down to four feet but they are not cheap. Used utility tractors of adequate performance and measuring six feet wide or less are readily available and cheap. For quality-driven growers, I strongly suggest buying a new tractor and planting on a 6-1/2 to 7-1/2 foot spacing. At the worst buy a used 6 foot tractor and plant on 8-1/2 foot rows. For cash-strapped production growers, use the 6 foot tractor and settle on 9 foot rows. In all cases plan on effectively managing your grape canopy or allow extra room.

Spacing in the row is easier to decide on. Closer in-row spacing increases planting costs, production costs and plant vigor. Wider spacing can make it difficult to fill the trellis, particularly with cane pruning. I suggest five to six feet between plants for a VSP and six to eight feet for a SHW trellis. Six feet works for both and will allow you to convert your training over later if desired.

4. Post and wire considerations: Standard vineyard wood line posts are 3" (min) by 8 feet long. End posts of 4" (min) by 9 feet long or 5" (min) by 8 feet long are the minimum acceptable. Steel posts are being used more and more as wood becomes more expensive. If you choose steel, use them for intermediate (line) posts only and use only the heavy gauge options. They still won't be as strong as wood. Space line posts a maximum of 21' apart for wood and 18' for steel. High tensile 12-1/2 gauge steel wire is the industry standard for fixed wires. Preferably drive posts small end down between 63 and 72 inches above ground. Uniformity is important here. Use 63" for narrow rows (6') and 72" for 9' rows. On a VSP trellis place your fruiting (lowest) wire at a level which allows for maximum shoot length while leaving your back intact. For narrow rows, 24" to 26" makes sense. For wider rows and taller posts 28 to 32" will work well. I prefer the range of 26 to 30". Don't, as some references suggest, place your first wire at 40 or 42 inches above the ground. You are wasting valuable trellis space and compromising the VSP trellis. For a SHW trellis all you need is a top wire 2" below the top of the posts. Other wires may be useful for pulling in errant shoots, but in general the number of wires required for a SHW trellis will be many fewer than that needed for a VSP.