Using a Vertical Shoot Position Trellis and Micro-Nutrients to Reduce Labor and Increase Fruit Set

Final Report for FNC03-478

Project Type: Farmer/Rancher
Funds awarded in 2003: $2,502.00
Projected End Date: 12/31/2005
Matching Non-Federal Funds: $4,093.00
Region: North Central
State: Minnesota
Project Coordinator:
Tim Gieseke
Minnesota Project
Expand All

Project Information


We have been farming for nine years with an eye toward gradually diversifying our operation as we see economic sustainability both in the short and long term. Our farm operation consists of 50 owned acres and 30 rented acres. Sixty of the acres are in corn and soybean production, 5 acres in small grains and the remaining 20 acres consist of a 5-acre farmstead, 5 acres of buffer strips, 1 acre field borders, 7 acres of pasture and hayland, a 1/4-acre vineyard, and a 1 1/2-acre black walnut stand.

The small grains, pasture, and hayland are used for the ewe/lamb operation. We have 15 ewes on rotational grazing and will be expanding the grazing operation in a step-wise fashion in the next couple of years as the flock expands.

We view our operation under the "economy of scope" lens, rather than the "economy of scale" lens program, in that, we are attempting to distribute capital and labor over most of the year rather than concentrate it during planting and harvest times.

In nine years of farming, we have identified conservation needs of the land and incorporated practices and structures such as contour curbs to assist in infiltration, a runoff pond to collect runoff, and increased crop residues throughout the year, and we have been able to utilize a neighboring farm’s manure for all nutrient needs. We have also taken fringe lands out of corn and soybean production and planted either grasses or trees. These fringe lands include grove, ditch, farmstead, and field edges.

In diversifying our operation, we choose to also include a wine grape vineyard using LeCrescent stock. LaCrescent (MN 1166) is considered to be one of the most promising new white wine selections for Minnesota’s climate, as it produces a high sugar content and its wine has a pronounced and delicious apricot-like flavor. The problems associated with this variety include high acidity of the grape, it is susceptible to poor fruit set, and it is moderately susceptible to soil-borne Powdery and Downy Mildew. More general problems with grape growing include labor costs associated with pruning and leaf removal for grape ripening can be cumbersome with differing structures of trellis.

We considered the positive attributes of the LeCrescent to be an opportunity for our operation, so we focused the SARE project on addressing the high acidity of the grape, to increase its fruit set and to prevent soil-borne mildews. High labor costs are associated with vineyards, in general, and remained an important aspect in finding solutions.

Our goals for the project were to create a larger, more uniform grape harvest with better grape plant and grape fruit quality, and in the process, reduce the labor requirements throughout the year, including reducing the labor required for harvesting the grapes.
Our process to achieve these goals started with our own education on the various trellis designs and why they are chosen, on what causes high acidity in grapes and modes of infection from mildews. It is in this stage that the producer must be open to challenges to their own ideas on how to address the particular issues.
Conversations with Gary Hahn, Hahns Vineyard; George Marti, Morgan Creek Winery; Ray Winter, Winterhaven Vineyard; and Peter Hemsted, Research Viticulturist University of Minnesota brought much insight into the operation decisions and informed us about the problems associate with their efforts. In addition to conversations, we also visited vineyards and assisted with some of the labor in caring for the vines. It was at a pruning day at the late Elmer Swenson’s vineyard that I was told of a trellis system that significantly reduced pruning labor requirements.

With the input from experienced growers, we were able to develop our own process to address these identified problems. This stage is also critical in that not all the opinions on how to address the identified problems are the same. The decisions made must be based on the best available science and experience, but also on your professional judgment.

To achieve these goals, we compared two Vertical Shoot Position trellis systems, a Low Cordon with Spurs (VSP-LCS) to that of an Upper Cordon with Drop Canes (VSP-UCDC). The VSP-UCDC has also been referred to as the more traditional Hudson River Umbrella trellis system, so called because the drop canes produce an umbrella-like feature.

The VSP-LCS has a cordon wire at 30 inches and a high wire at 70 inches. In between, two sets of wires are used to provide a framework for the vine. The cordons are trained on the 30 inch wire and shoots are directed vertically. The VSP-UCDC has a wire at 30 inches and a high wire at 70 inches. The vine is trained to grow to the top wire and cordons are trained horizontally with canes growing to form a umbrella-type structure. The VSP-LCS contains 6 wires and the VSP-UCDC contains 2 wires.

The trellis was installed on the western side of a hill that also had a slight orientation to the north. Within the parameters of our operation, this site provided us with the best air and water drainage. Our first instinct was to protect the vineyard from the winter winds, but after consultation, it was determined that because the grapes are winter hardy for our area, we should choose the location to address the larger potential threat of stagnant, moist conditions that become ideal for mildew establishment.

Of the six trellis rows, four were installed using the VSP-LCS and two were installed using the Hudson Umbrella system. Each row consisted of eight "panels" with each panel containing three vines. The vineyard contained 144 vines. Below each row, a 3-foot wide plastic woven weed barrier fabric was laid down to retard weed growth and prevent soil borne organisms from being splashed up onto the grape leaves.

To determine if fruit set was enhanced through a foliar micronutrient application, three treatments types and a control set was used. Random selection of 3-vine panels were picked for a boron application, a zinc application, a boron-zinc application and the control, in which no application was made. The application plan is detailed in Table 1. Soil tests were conducted for boron and zinc in October, 2004. Petiole samples were collected prior to foliar application and analyzed for boron and zinc. Foliar applications were conducted after leaf out and before fruit set.

Table 1. Trellis Treatment Panels

VSP Trellis
LCS 1A 1B 1C 1D 1E 1F 1G 1H
LCS 2A 2B 2C 2D 2E 2F 2G 2H
UCDC 3A 3B 3C 3D 3E 3F 3G 3H
LCS 4A 4B 4C 4D 4E 4F 4G 4H
UCDC 5A 5B 5C 5D 5E 5F 5G 5H
LCS 6A 6B 6C 6D 6E 6F 6G 6H

Micronutrient Treatments:

Boron – 1H/2C/2E/2G/3D/3G/3H/4E/4G/5A/6C/6G/6H

Zinc – 1A/1D/1E/2H/3A/3C/4B/4H/5B/5D/6E/6F

Boron/Zinc – 1C/1F/1G/2A/2B/3B/4C/4F/5G/5H/6D

Control – 1B/2D/2F/3F/4A/4D/5C/5E/5F/6A/6B

We felt the results of the overall project were a success, despite a severe weather event decimating the crop and impacting part of our study.

The location of the vineyard has proved to be a very good site, in that, since planting the vineyard in May, 2003 we have not had an identified problem with mildew. Situated on the hillside, dew forms lastly in the evening and is the first location in which dew evaporates. Even during humid, still days the topography allows for a slight breeze. The weed barrier fabric is still in place with vegetation growth between the rows being mowed as needed. Weeds do encroach onto the edges of the fabric and at the location of the hole in the fabric where the vine comes through. With the size of the vineyard it has been practical to manually pull the weeds from the vine location. The weeds encroachment from the edges is not seen as a problem, except for a few spots of more aggressive growth.

Soil tests indicated boron levels at 0.8 ppm and zinc levels at 6.0 ppm. Petiole tests indicated boron at 38 ppm and zinc levels at 18 ppm. Soil levels were adequate for both boron and zinc. Petiole samples indicated a deficiency in zinc and with sufficient boron levels.

With a well drained location and the use of the weed barrier fabric to prevent weed overgrowth and soil borne organisms that splash up and infect the grapes, we have not used chemical pesticide treatments for weeds or mildews, or for any other use.

The VSP-LCS trellis system appears to reduced labor and provides more even and earlier fruit ripening. Although the initial growth of the vines appear to favor the more vertical growth of the Hudson River Umbrella trellis over the somewhat forced horizontal cordon growth of the VSP-LCS, by mid-summer growth mass appear to be equal and perhaps begin to favor the VSP-LCS as the vine is allowed to spread out.

The VSP-LCS is a better framework to spring prune, in that, spur cuttings are readily displayed along a horizontal cordon rather than bunched up in an umbrella formation. Because of the relative young age of the vines, and the lack of years of growth, the differences in pruning labor was probably not as pronounced as it will be in a few years when the umbrella formation would become denser and potentially intertwined.

The analysis for the micronutrient treatment for determining fruit set could not be completed due to an August 3rd storm that included 85 miles per hour winds. Surprisingly, very few grapes clusters or leaves were removed from the storm, but bruising occurred on most of the clusters and within 10 days, a loss of more than 90 percent of the crop estimated.

The VSP-LCS provided a better framework for grape ripening. On the VSP-LCS, grape bunches are more exposed to sunlight that promotes grape ripening and acid reduction. Both aspects are important for LeCrescent grape growth in southern Minnesota.

Our plans to sell our grapes to Morgan Creek Vineyards did not materialize due to the storm related losses. On September 3rd, we checked the sugar content of the grapes using a Brix meter, we visually inspected and tasted the ripeness and determined that the grapes were ripe. We harvested just 42 pounds of grapes. Upon gathering the grapes, they looked much less ripe than in the field. Because of the limited supply, we pressed our own juice and began the winemaking process. We checked the sugar content and it was adequate at 21.5 Brix. The acidity was high at 1.4 total acidity.

After the experience of this project, we feel confident that we should eventually convert all the rows to the VSP-LCS. The framework of this trellis system spreads out the vine to provide a larger and more even growth panel than the Hudson River Umbrella system. It provides more ease when working with the vines. Despite the extreme crop loss, it did also seem apparent that ripening would occur more evenly and earlier. We will leave some panels in the Hudson River Umbrella system to further support our findings, but only in limited amount due the varied and later ripening.

This observation was also made by a Minnesota vineyard and reported on their website. Great River Vineyard, in a comparison of the High Wire Renewal System (Hudson River Umbrella) and a VSP-LCS with Frontenac Gris, found ripening had occurred up to a week earlier and acid levels were at .77 instead of 1.4 total acidity on the VSP-LCS.

Utilizing this VSP-LCS may create conditions in which the growing season can be reduced up to 10 days and it is possible to develop a grape quality more ideal for wine making. These 10 days can be quite important as September brings diminishing growing conditions and migrating birds.

The installation costs of the VSP-LCS are slightly higher due to the use of more wire and wire accessories, but the costs are not significant relative to benefits.

The weed barrier fabric appeared to perform its function well in that it greatly reduced weed pressure and prevented soil splash up. The fabric did not let in water as readily as expected, but it did appear to keep the soil moist under the fabric. Some of the soil does seem hard under the fabric. Eventually we would like to convert the fabric covering to a mulch and wood chips.

Because the soil tests showed adequate levels of boron and zinc micronutrients, but the petiole samples showed deficiencies in zinc, it could be assumed that the zinc treated vines may have shown improvement if yield checks could have been performed. Other vineyards have had success in foliar applications and we will continue to conduct petiole testing and foliar applications as needed.

The overall project has had a positive effect on our farm operation. We feel there is a high probability that our wine grape operation will produce a higher quality grape with less labor, although this will be confirmed in future growing seasons.

If other producers are interested in growing grapes in the Upper Midwest, I would recommend that a VSP-LCS trellis be seriously considered for reducing labor, and as or more importantly, for the early ripening and reduced total acidity.

To further confirm our findings and those of the Great River Vineyard, we will keep a few panels growing in the Hudson River Umbrella system to be able to compare ripening, grape sugar content and acidity.

We conducted outreach through hosting a field tour day on September 1, 2005. We worked with Gary Wyatt, University of Minnesota Extension staff to provide media releases. Coverage on the event was wide-spread with both radio and newspaper promotion pieces, including a notice that was run in the Agri-News, a regional weekly paper out of Rochester, Minnesota. Similar notices were run in local papers as well. Radio notices were heard on KNUJ-New Ulm.

Fifteen people attended the event. Most of the attendees were from a 10-mile radius from our farm, although we had some come from 30 miles away and the farthest traveling from Minneapolis which is 80 miles away. Several were grape growers, but on a backyard scale. The attendee from Minneapolis is planning to return to her family farm and would like to diversify the operation.

Two handouts were developed for the attendees. One handout described the grant proposal and activities. The other handout described how the vineyard fits into our farming operation from a time and labor perspective. A reporter from the LaFayette Ledger, a local weekly newspaper also attended and featured our tour on the front page of the following week’s paper.

A summary of the final report was also provided to the editor of the Minnesota Grape Growers Association for publication.


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.