Final report for FNE20-959
Project Information
Our objective with this research was to test cost effective protective coverings and their ability to limit winter freeze damage to our european (Vitis vinifera) grapevines. Several protective coverings were used in this study; plastic sheeting, Hibertex geotextile, and soil. Several of these coverings were used in different configurations. Data loggers were used to record differences between the temperature under the coverings and the outside air. Harvest weights were the primary measurement used to judge effectiveness of these coverings. Hibertex geotextile used in a high hoop configuration yielded the best results both from a harvest yield and cost effectiveness. This study’s results will affect how Black Birch Vineyard utilizes protective coverings in the future. Many of the methodologies were shared with growers in New England at growers meetings.
This project seeks to increase the winter survival of cold-sensitive grape varieties in New England through the use of lower-cost cold protection systems that have not been tested in the northeast under extreme cold conditions. In addition to the testing of the physical tenting and modified low-hoop systems, we will combine some covered protection systems with treatments to induce cold-hardiness in the vines. Our covered systems will be compared to untreated vines, vines that are buried in the winter months, with vines protected by a small high hoop system as a reference treatment. Our objective is to provide data that will allow determination of the best systems to provide cost-effective cold protection for grape production in cold climate states.
Approximately 5-15% of vineyard production is lost in the US to cold damage annually, and these losses are greater in the northeastern US where vineyard owners struggle to produce a quality product from cold-sensitive Vitis vinifera, while battling extreme winter cold as well late-spring frosts. Preventing cold injury to vines is a key viticulture concern in many grape growing regions (Evans, 2000; Zabadal, Dami, & Goffinet, 2007). European grape varieties such as Cabernet Franc grown in California and most of the world, are desirable because of both quality and marketability of the wine produced. American grape stock, such as V. labrusca and V. riparia are cold-hardy but are less desirable from a marketability standpoint and wine produced particularly V. labrusca varieties, can have undesirable qualities such as a “foxy musk” flavor that reduces the quality of the wine.
- vinifera varieties are therefore grown by many vineyards in the northeast even though the risk of losing an entire season’s production from freezing events is very high. Indeed, vineyards neighboring our Black Birch Vineyard have lost all or most of the harvest from Cabernet Franc vines in three of the last eight years, but we have persisted in planting ‘Cabernet Franc’ and other V. vinifera varieties (on American rootstock) because it produces good yields and we have produced excellent wine in years where the entire crop has not been lost. V. vinifera vines are killed at temperatures below -21C (-6F), and our vines have been killed outright in severe winter cold events (two nights of -18F as an example). Late frosts that have occurred in May after several inches of new growth have already been produced have also been a problem. Our region has adequate growing degree days and conditions to produce excellent wine; however, the 4 or 5 cold-related events each year prevent consistent success. As such, our problems are different from other areas of the country (California, Arkansas, Pennsylvania and warmer peninsular regions of Michigan) where extreme cold weather is not a concern and vine protection is removed in winter.
Our goal in this research is to increase the winter survival of cold-sensitive grape varieties in New England.
We propose to test different types of protected agriculture systems combined with other treatments that can reduce cold injury.
The three protected systems that we propose to compare are: 1) a low-tent system using both geotextile fabric and greenhouse plastics which, in limited Canadian research trials have been useful for vine protection, 2) a modified low hoop system (“trellis-hoop”) system, and that we propose as a lower-cost, low maintenance design for cold protection, and 3) a conventional high tunnel system, which has proven cost-effective for high-value grapes. In combination with these physical protection systems, we would also run comparative tests with a novel cold hardiness-inducing treatment, ChillBanTM, under development at Oregon State University.
Our research will include a cost-benefit analysis to demonstrate whether the systems would be cost-effective, and to show where improvements could be made to further reduce costs while improving yield/quality. We would compare the tenting, modified trellis-hoop and high tunnel to Control/Reference treatments, which will include uncovered vines except for the graft union and complete vine burial during the winter months, which has been used with some success in Canada (although lower yields with more disease is reported to occur with vine burial systems). ChillBanTM will also be integrated in our tests. Ambient temperature, relative humidity and soil moisture content will be monitored for each treatment to determine when ventilation of covered systems is needed, and to assess the frequency of damaging cold and spring frost temperatures. We will assess nine treatments as outlined in the Methods and Materials section of this proposal.
Both positive and negative results may occur with the protected systems and these will be reported. Downy mildew and mite activity can increase depending on how humidity is regulated, whereas insect pests like Japanese Beetle have been reported to be greatly reduced (Chien, 2011). Vine damage due to overheating in winter months may occur if venting is not done judiciously. However, reduced cold injury should also decrease occurrence of crown gall (Agrobacterium) infection.
Many vineyard owners throughout New England have similar problems with winter damage that we experience in our vineyard, and we are proposing using our vineyard as a model cold-protection test system. We propose working in cooperation with UMass Researchers and Extension personnel as outlined in the Outreach section and the appended Support letters.
Black Birch Vineyard is a farm winery located in the Connecticut river valley of Western Massachusetts. Our acreage under grapevine cultivation is 18 acres, which consists mostly of Vinifera or European grape varieties. These varieties include; Pinot Noir, Chardonnay, Cabernet Franc, Riesling, Gruner Veltliner, Traminette, and Marquette. Our typical harvest is 20-30 tons of fruit, all of which is used to make our wine.
Our vineyard employs 3 full time and 5 part time crew members. The vineyard is managed by Ian Modestow, one of the owners. We are a woman owned farm.
80% of our sales occur at our vineyard directly to customers. The remaining 20% of our sales is to stores and restaurants within a 40 mile radius. We currently have a wine club of over 600 members.
Cooperators
Research
Methods were followed as proposed:
We will test Cabernet Franc vines, planted in 2016 at our vineyard using a VSP training system:
Protected Agriculture Treatments:
- A “tenting” system using both greenhouse plastic, or geotextile (HibertexPro) covering (separately) will be used based on systems similar to those tested in Ontario (Willwerth, 2013) (Figure 1). Shoots higher than the lower cordons will be detached or pruned as necessary to allow the protective sheets to cover the vines. Protection was placed on the metal stakes to prevent perforation of the fabric/plastic.
Note protection from perforating the plastic. This was done on all pieces that were placed 
Edges of the fabric were secured with large pieces of cordwood.
- A modification of a low tunnel system (“trellis-hoop” system), will be used as described in Figure 2. HiberTexPro fabric will be draped over the top of arched PVC tubing, secured to both the top of trellis posts, and also at 10-ft intervals along the top wire. Soil sacks and clip-stakes will be used to secure ends to the soil.
- The high tunnel was removed from the research treatments
Ventilation of all systems (rolling up the side fabric) would occur much of the year to allow vines to harden off and acclimate. We anticipate the systems would be covered in the 3 coldest winter months and during spring frosts. Temperature monitoring will cue us to vent on sunny but cold days, when temperatures increase above 30F inside the tunnel/tents for extended periods.
Induction of cold-hardiness: Following the recommendations of developere Clive Kaiser from OSU, 2 applications of Chillban were made on two different dates. These applications were made with a Solo, PackBlast sprayer. Researchers at Oregon State University have developed a novel proprietary plant coating, ChillBanTM that induces cold tolerance in apple and grapes. Limited testing of cold-hardy induction treatments on grapes has occurred at the extreme temperatures that we have in the northeast. The treatment is a food-grade plant-based coating that, in addition to enhancing cold-hardiness, also increases fruit sugar content, firmness and speeds-up maturity by 7-10 days. Application will follow recommendations by cooperators Professors Clive Kaiser at OSU and Barry Goodell at UMass: A knapsack mist sprayer will be used to apply the material at a rate of 60 gal/acre (droplet size >150 µm, with travel speed <2 mph), with 3 treatments in August, September and early October.
Vine-Burial: Winter vine-burial treatment (vines detached from the wires and buried through the winter) will be compared to the protected covering treatments and to untreated Control vines. Prior studies with soil-burial in eastern Canada have shown that burial is effective for winter-shelter, but that yield is reduced and damage to the vines with increasing disease can occur. Burial will require coverage with 2-inches of soil after detachment of the vines from the wires, and will occur in late October after harvest and before soil freeze-up. Unburial will occur in April after soils have thawed.
Data Collection: Temperature/humidity loggers
will record at 15-minute intervals throughout the test plots, and soil moisture content will be assessed on a weekly basis. Irrigation will be initiated as required in summer months. Vines will be assessed for overall health and the development of disease/pest problems weekly. Frequency of spray treatments and disease assessment will be recorded in consultation with UMass cooperator Petit. Grape yield/quality will be assessed by weight and Brix measurement, and ultimately by the quality/volume of wine produced. A basic cost-benefit analysis will be conducted with support of University collaborators (see letters of support) and will include all recurring and non-recurring costs and projected benefits, and will be conducted over the 5-year anticipate lifespan of greenhouse/geotextile fabrics.
Our overall design uses 36 vines/treatment broken into 18 vines sections. These sections were done to keep the treatment areas similar with regards to soil. Our proposed treatments are:
- Untreated vines (controls) with no protective treatments other than soil-burial of the graft zone.
Untreated Cabernet Franc vines - Vine burial in winter after detachment of vines from the trellis.
Following initial pruning and laying the canes down on to be covered with soil - Vines treated similarly to the Controls in #1 above except that a proprietary cold-hardiness treatment will be applied in Autumn.
- Vines, tented using greenhouse plastic from the low wire, in a manner similar to low hoop protection of ground crops. The graft union will be unburied but protected by the tunnel warmth.
5. Same as #4 above but using a double-layer, with row plastic used under the greenhouse plastic.
6. Pruned vines, tented similar to #4 above, but using HiberTex Pro (preliminarily tested in Canada with grapes). This is an experimental system in the northeastern US and appropriate timing/methods for ventilation for heat and humidity must be determined.
7. Use of pruned vines with polyester geotextile as in #6 above, but also with the addition of the cold-tolerance inducing spray as outlined in #3 above.
8. Vines protected with the “trellis-hoop” system with HiberTex Pro. Potential advantages over the tenting systems (#4, 5 and #6 above) include reduced contact between the vines and the covering, greater capture of heat from the ground, and provision of more uniform ventilation on sunny days to prevent vines coming out of dormancy.
9. This high tunnel treatment, which was previously here, has been eliminated from the study
Total: 216 vines.
Monitoring will include:
- Temperatures inside and outside each treatment unit using automated data loggers (15-minute temperature and humidity readings).
- Number of times the protected systems require venting during winter months.
- Soil moisture (taken weekly using moisture probes)
- Vine death and necrosis after the winter
- 5% Bud survival for 100 buds on 10 canes/treatment.
- Disease or Insect Pest rating over the summer including number of times spray treatment for insects and disease is required
- Veraison
- Grape harvest yield (weight)
- Sugar (Brix)
Summary of procedures as performed: Eight treatments to protect vines from extreme cold events were tested on Cabernet Franc vines in a western Massachusetts vineyard over a 2-year period. Treatments included: vine burial, a proprietary plant hormone spray (ChillBan) used only in year-1 due to availability, and row coverings with 6 mil sheet plastic in either single or double layers, or with a single layer of a nonwoven geotextile thermal barrier (Hibertex™). In one treatment, the plant hormone treatment was combined with Hibertex covering in year-1, and Hibertex was also used separately both as a low hoop covering and a whole trellis covering; the latter was termed “high trellis hoop”. Berry yield value per 12-plant row was calculated based solely on the costs of yearly pruning and harvest. Costs for each treatment were calculated as the cost of the materials required for each treatment, plus the labor costs required to apply the treatment ($18/hr wage). Labor costs for treatment removal or unburial and reattachment of the vine to the trellis was also included when coverings or vine burial was done. Row covering or vine burial was conducted in late November to early December. Covering removal and unburial of vines that were buried was done in early March. All treatments were conducted on 2 rows of 12 vines (24 plants/treatment) except for the Controls which were 3 rows of 36 vines. The second-year results are discussed.
This image shows all the temperature data from all the rows with the minimum, maximum and average temperature in the winter of 2021-2022. Noteworthy is the recorded low of -13F in the control, which is certainly cold enough to damage Cabernet Franc buds.
All the below graphs are the individual row temperature data from winter 2021-22 compiled on February 5, 2022.
Below is the temperature data from the 2020-21 winter from all of the test blocks. The first image is all the loggers set to the same timeframe. Obviously different colors represent different rows.
Below shows each row with with the high, low and average temperature from the 2020-21 winter. The red flags note any concerns we had for a particular row. One of our data loggers malfunctioned and was not recording properly. One was presumably covered in snow affecting its readings. Due to some inconsistencies in these loggers the decision was made to switch to another type.
Below are the temperature data from each logger in the test study.
Below is analysis from the 2021 growing season. This analysis was made from data collected on shoot growth (length), disease pressure, harvest yields, and harvest brix. These slides are working and not the completed analysis. Elsa Petit from the University of Massachusetts present this material to the New England Fruit Grower's meeting this year and are taken directly from her presentation.
Initial results, taken from only December during which we had a what I'd consider a 'cold-event', with temperatures reaching -20C, proved suprising. 
The above graph shows the cold dip that occurred on December 18th. The below graph shows the temperature inside the treatment group #5 during the same evening.
Note that the above graph only shows a low temperature of -14, more than a 6 degree difference! Of course we are waiting for the real cold winter days to happen but this initial result is encouraging!
BACKGROUND INFORMATION AND COSTS:
- Labor Costs: $18/h
- One Row of Grapes = 12 plants (vines)
- Value of Grapes to the Vineyard Owner: Based on Cost of Pruning plus Cost of Harvest of Controls ($27/row), divided by Control Yield (4547.3 g/Row): 1000g = $5.94. US$5.94/kg harvest weight
- Conversion of Yield/kg of Grapes per 12-vine Row to US Dollars in Table 1.
Material Costs per Row:
Hibertex Low Hoop (10 yr. lifetime) = $69.72. Divided by 10 yrs = $6.97/y
Hibertex High Hoop (10 yr. lifetime) = $139.44. Divided by 10 yrs = $13.94/yr
Plastic (6 mil) Double (6 yr. lifetime w/ 4yr UV): $75 x 2 = $150. Divided by 6 yrs = $25/yr
Plastic (6 mil) Single (6 yr. lifetime w/ 4yr UV) = $75. Divided by 6 yrs = $12.50/yr.
ChillBan Cost = $0.23/row of 12 plants, 2x applications per year = $0.43/year
Table 1. Grape cluster yield (kg) per 12-plant row and calculated dollar yield per row based on a $5.94/kg of grapes value to Black Birch Vineyard.
|
Cold protection row treatment |
Average Grape cluster yield (g) per vine. [Std Dev] |
Grape cluster yield average per row (g) |
Grape cluster yield per 12-vine row, converted to US dollars based on $5.94/kg value to Black Birch vineyard |
|
High Trellis hoop – Hibertex |
945.5[567.2] |
11345.7 |
$ 67.39 |
|
Low hoop – Hibertex + ChillBan |
927.4[555.9] |
11128.3 |
$ 66.10 |
|
Vine Burial |
915.3[958.5] |
10983.7 |
$ 65.24 |
|
Low hoop – Hibertex |
734.2[502.8] |
8810.2 |
$ 52.33 |
|
Low hoop – double plastic |
639.4[572.4] |
7672.2 |
$ 45.57 |
|
Control (36 vines) |
378.9[363.7] |
4547.3 |
$ 27.01 |
|
ChillBan No Cover-2 |
294.8[288.3] |
3537.4 |
$ 21.01 |
|
Low hoop – single plastic |
164.3[97.4] |
1971.4 |
$ 11.71 |
Time/Labor Costs Per Row
High Hoop (2x laborers)
Hibertex: winter-placement and spring-removal = 20 min + 10 min = 30 min
Hibertex: Pruning (Spring): 30 min
TOTAL (2 laborers): 120 min = $36/row
Low Hoop (2x laborers)
Hibertex: winter-placement and spring-removal = 30 min + 15 min = 45 min
Hibertex: Pruning (Fall): 30 min
TOTAL (2 laborers): 150 min = $45/row
Plastic: Single layer winter-placement and spring-removal = 30 min + 15 min = 45 min
Plastic: Pruning (Fall) Single layer: 30 min
TOTAL (2 laborers): $45/row
Plastic: Double layer winter-placement and spring-removal = 40 min x 20 = 60min
Plastic: Pruning (Fall) Double layer: 30 min
TOTAL (2 laborers): $54/row
Vine Burial (2x laborers)
Pruning and burial (Autumn, digging not mechanized): 40 min
Unburial and Re-attachment to trellis (springtime): 80 min
TOTAL (2 laborers): $72/row
ChillBan no-cover (single laborer)
Application with Backpack Mist Blower (1 person): 2 hrs x 2x applications/year = 4 hrs
TOTAL (single laborer): $72/row
Controls (2 laborers)
Pruning: 30 min. (2 laborers) = 1 hr. TOTAL: $18/row
Table 2. Total yearly costs per row, and yield value comparison, for each cold protection treatment.
|
Treatment |
Cost of Labor/Row |
Cost of Materials/Row |
Total Costs/ Row |
$ Value/Row (from Table 1) |
Net $ Value/Row (minus Costs) |
|
**Hibertex High Trellis Hoop |
$36 |
$13.94 |
$49.94 |
$67.39 |
$17.45 |
|
Hibertex Low Hoop + ChillBan |
$45 + $72 |
$6.97+ $0.43 |
$124.40 |
$66.10 |
-$58.30 |
|
Vine Burial |
$72 |
0 |
$72 |
$65.24 |
-$6.76 |
|
*Hibertex Low Hoop |
$45 |
$6.97 |
$51.97 |
$52.33 |
$0.36 |
|
Plastic Double, Low Hoop |
$54 |
$25 (2-layer) |
$79 |
$45.57 |
-$33.43 |
|
*Controls |
$18 |
0 |
$18 |
$27.01 |
$9.01 |
|
Chillban, 2x/yr. no cover (1styr) |
$72 |
$0.43 |
$72.43 |
$21.01 |
-$51.42 |
|
Plastic Single, Low Hoop |
$45 |
$12.50 (1-layer) |
$57.50 |
$11.71 |
-$45.79 |
*Treatments where the “Net Value” for application of a specific treatment is positive.
**Treatment where the “Net Value” provided enough benefit to approximately equal costs of all pruning of the control vines.
Uncovered vines (controls and ChillBan with no cover), and single the plastic covering, generally yielded lower average berry weight per row compared to other treatments (Table 1). Observations of vines after row covering removal in the spring showed that plastic coverings had more rodent damage, and this damage was present even in the upper regions of the cordons. The double plastic low hoop covering provided higher berry yields than the single plastic low hoop covering, but the double plastic treatment still suffered some rodent damage resulting in lower yields compared to the best treatments.
High yielding treatments included the Hibertex high trellis hoop and Hibertex low hoop (with or without ChillBan), and vine burial. The Hibertex high trellis hoop treatment stood out because it was one of the best berry yield treatments providing approximately enough value over and above the costs of materials and labor to also cover the costs of pruning of control vines. In addition, the high trellis hoop Hibertex covering was quicker and easier to install, remove and store without the need to prune extensively prior to covering the vines in the winter. Vine burial stood out because of high berry yield, but labor costs for burial and unburial were high and exceeded the costs of treatment. However, for vineyards with low-cost labor, vine burial may be a good option. The performance of ChillBan could not be assessed because supply was unavailable for year-2 treatments. However, in year 2 the Hibertex low hoop treatment combined with ChillBan was one of the top yielding treatments even though ChillBan without row covering provided no, or even negative, benefit compared to controls. The costs for mist application were high causing this treatment to exceed the added value of the treatment; however, as with all treatments, costs would be reduced with scale-up. Thus some treatments that did not show a net positive value in this study (Table 2) might provide more value once scaled for an entire vineyard. Similarly, mechanization of processes ranging from vine burial to the installation of fabric could reduce costs and improve the net value of treatments.
The data suggest that in northern vineyards with Vinifera grafted vines that experience even occasional nighttime temperatures below -20º C that vine coverings with a thermal geotextile can provide significant benefit. Cost and yield calculations (Table 2) show that both low hoop and high trellis hoop coverings with the nonwoven Hibertex geotextile would provide cost-effective treatments for increasing yield. The high trellis hoop Hibertex treatment provided a highly cost-effective treatment because of the boost in yield and ease in installation/removal.
Education & Outreach Activities and Participation Summary
Participation Summary:
Summary report produced:
DRAFT 2 - Cost Benefit Analysis for Cold Protection of a Vinifera Vineyard in Western Massachusetts.docx
Powerpoint presentations used to present research so far:
Cold Protection in Grapes by Elsa Petit: cold protection 2022
Data: GP-Feb14 - Grape covering temp plots (F)
Learning Outcomes
A great deal of knowledge was gleaned from completing this study pertaining to methods of protecting grapevines from cold winter events. Most of the study produced new ideas and information for using novel methods used to protect grapevines from winter cold events. Although currently none of these changes have been permanently adopted at my vineyard
Project Outcomes
A great deal of knowledge was gleaned from completing this study pertaining to methods of protecting grapevines from cold winter events. Most of the study produced new ideas and information for using novel methods used to protect grapevines from winter cold events. Although currently none of these changes have been permanently adopted at my vineyard