Vine Lines: Petiole Sampling To Monitor Grapevine Nutrient Status

Vine Lines: Petiole Sampling To Monitor Grapevine Nutrient Status

Farming is all about timing. Some of the things we need to do are time-flexible like pruning, while others are time-sensitive like applying a spray for powdery or downy mildew. Missing a spray to control mildew can leave you with a problem for the rest of the season. Monitoring the nutrient status in vines is also a “time-sensitive” activity.

Bloom And Veraison Petiole Sampling

The best way to find out what fertilizers you might need to apply is to analyze “petiole” (leaf stem) samples at bloom time and again at veraison (berry softening). Bloom time is important because insufficient levels of micronutrients at bloom can have a season-long effect on fruit quality. Veraison is important since at this time there is a major change occurring within the vine (the beginning of fruit ripening). This involves the uptake and remobilization of macronutrients (potassium in particular).

For vinifera (European/California) varieties, research work has been completed on both bloom time and veraison vine growth stages to establish desirable levels for individual nutrients. For the labrusca and hybrid varieties, critical nutrient levels are established for veraison with research underway for desirable levels at bloom time.

Sampling Procedures

When sampling at bloom time and veraison, it is important to use a consistent approach each year.

• Vineyard Location(s): If a vineyard is uniform in growth, you can select one location. If one area has consistently better growth than another, you may select two areas to sample. For each area being sampled, select specific rows that are representative and use the same rows each season.

• Timing and Petiole Position: For the bloom time sample, the vines would ideally be at 70% to 80% bloom (50% to 100% bloom is OK, too). If you are ahead of or behind this timing, it should be noted for each sample. At bloom, the petioles sampled should be the ones opposite the first grape cluster. For a veraison sample, the sample should be obtained at the beginning of berry softening with the petiole obtained from a mid-cane position. A total of 70 to 80 petioles are sufficient for each sampled area. When taking a sample, snap off the petiole and blade from the cane, then discard the leaf blade and save the petiole.


• Varieties and Rootstocks:
Don’t mix varieties. While critical levels of some nutrients are the same across varieties, there can be significant differences. Research during the last 10 years has also identified significant differences in nutrient uptake among rootstocks. Therefore, don’t mix rootstock samples.

• Sample Handling: Petiole samples should be placed in a paper bag and labeled with the location, row number, growth stage, and date. The samples should be delivered or shipped to an agricultural laboratory. If there is going to be a delay in delivery, the paper bags should be left open to air-dry. Do not use plastic bags since this can result in molds growing on the green tissue.

Interpretation Of Results

There are a number of laboratories across the U.S. that can perform an analysis of your samples. The Extension service (farm adviser) offices in each state typically maintain a listing of agricultural laboratories. You should not use an environmental laboratory since their fees are higher than ag labs.

You will want to run a “complete” analysis which will include the macronutrients (nitrate-nitrogen, total nitrogen, total phosphorus, potassium, calcium, and magnesium) plus the micronutrients (sodium, boron, zinc, manganese, iron, and copper). Other micronutrients might be included depending on the area.

When you submit your sample, tell the lab that the analysis is for grapes, the type of grape (vinifera, labrusca, or hybrid), the variety, and the growth stage (bloom or veraison). Based on these sampling parameters, the lab should print the critical levels for each nutrient across the bottom of the report. It is important to ask the lab if the critical levels that they include in your report are based on university research or their personal experience. Unfortunately, sometimes labs develop their own set of critical or desirable levels for individual nutrients and do not indicate the basis of these numbers. It is not that the values that a lab uses are not appropriate, but you should be aware of their source. It is also a good idea to use an “independent” lab, not one associated with an ag chemical dealer.

Survey Sampling Versus Problem Diagnosis

A good vine nutrition monitoring program would include “survey” sampling at bloom time and veraison every year. In addition, there may be noticeable differences in vine growth or leaf symptoms within a vineyard that appear to be due to a nutrient deficiency or excess. Obtaining “symptom vs. non-symptom” or “good vs. poor” growth samples can frequently let you know if the problem is nutritional or not.

Topics:

Leave a Reply

Grapes Stories
The canopy of the vines that received the under-canopy sprinkler irrigation just on hot nights during heatwaves appear to be healthier than the control vines and have a higher yield.
Photo: Michael McCarthy
Grapes
February 5, 2016
Researchers Test New Method To Mitigate Vine Heat Stress
The use of evaporative cooling in vineyards during hot weather isn’t a new concept, but researchers in Australia are testing Read More
La Crescent produces a good quality white wine with apricot-like flavor. The off-dry, sweet white wine pairs well with appetizers, seafood and chicken. La Crescent has excellent winter hardiness with moderate disease resistance that requires a standard spray program.
Grapes
February 4, 2016
Northern Grapes Project Fuels A Market For Cold-Hardy Grapes
 There’s a burgeoning market for cold-weather grapes. The Northern Grapes Project, funded in 2011 by a USDA National Institute of Read More
wine barrels
Grapes
February 2, 2016
Unified Wine & Grape Symposium Sets Attendance Record
Winegrape professionals from around the globe gather for the nation’s largest wine and grape industry show. Read More
California Association of Winegrape Growers
Grapes
January 29, 2016
California Association Of Winegrape Growers Elects New Board Officers And Members
The California Association of Winegrape Growers (CAWG) has elected five new officers and three new members to its board of Read More
snow vineyard grapes winter
Grapes
January 29, 2016
Tips To Prevent Winter Injury
After two consecutive harsh winters, grapevine freeze protection is top of mind for many Eastern and Midwestern growers. Here’s a Read More
A vineyard worker first cuts the young canes out of the trellising. (Photo credit: Christina Herrick)
Grapes
January 28, 2016
Bending Down Vines Helps Young Growth Survive Sub-Zero Temperatures
An old tradition gone by the wayside is new again when it comes to vineyard winterization in the Great Lakes region. Read More
Cross section of Fiesta bud anatomy. Arrows indicates the two cluster primordia in the primary bud.
Grapes
January 22, 2016
Bud Dissection Can Guide Winter Grapevine Pruning Decisions
Bud dissection can help growers predict yield variation and adjust the number of spurs left when pruning. Buds are dissected Read More
The Latest
Grapes
February 10, 2016
Restoring The Napa River
The Napa River, which has helped create soil perfect for grape-growing in the Napa Valley, is in danger. Fortunately, conscientious Read More
Apples & Pears
February 9, 2016
State Of The Fruit Industry 2016 [VIDEO]
According to an national poll of fruit growers, fruit industry suppliers, and researchers, the market is poised for growth in Read More
Grapes
February 5, 2016
Geotextiles Can Help Prevent Winter Grap…
Although Northeast and Midwest grape growing regions have so far been spared from extreme cold this year, the winters of Read More
Grapes
February 5, 2016
Researchers Test New Method To Mitigate …
The use of evaporative cooling in vineyards during hot weather isn’t a new concept, but researchers in Australia are testing Read More
Grapes
February 4, 2016
Northern Grapes Project Fuels A Market F…
 There’s a burgeoning market for cold-weather grapes. The Northern Grapes Project, funded in 2011 by a USDA National Institute of Read More
Grapes
February 2, 2016
Unified Wine & Grape Symposium Sets …
Winegrape professionals from around the globe gather for the nation’s largest wine and grape industry show. Read More
Grapes
January 29, 2016
California Association Of Winegrape Grow…
The California Association of Winegrape Growers (CAWG) has elected five new officers and three new members to its board of Read More
Grapes
January 29, 2016
Tips To Prevent Winter Injury
After two consecutive harsh winters, grapevine freeze protection is top of mind for many Eastern and Midwestern growers. Here’s a Read More
Grapes
January 28, 2016
Bending Down Vines Helps Young Growth Su…
An old tradition gone by the wayside is new again when it comes to vineyard winterization in the Great Lakes region. Read More
Grapes
January 22, 2016
Bud Dissection Can Guide Winter Grapevin…
Bud dissection can help growers predict yield variation and adjust the number of spurs left when pruning. Buds are dissected Read More
Grapes
January 22, 2016
Enzyme Discovery Sheds Light On Pierce’s…
Plant scientists have discovered an enzyme that appears to play a big role in the leaf scorch that accompanies Pierce’s disease. The discovery could lead to new tools to combat the disease. Read More
Apples & Pears
January 20, 2016
Herbicide Flood Irrigation Application A…
Crops include stone fruit, pome fruit, grapes, tree nuts, and olives. Read More
Grapes
January 7, 2016
Gerawan Farming Shuts Down Table Grape O…
Gerawan Farming announced it’s planning to fully close its table grape operation effective Feb. 25, 2016. According to a Worker Read More
Grapes
January 7, 2016
New Wine Series Highlights The Women Beh…
When Meaghan Frank, general manager of Dr. Frank’s Winery, in Hammondsport, NY, tells the story of her family’s business, it Read More
Grapes
December 31, 2015
Tips For Canopy Management On Open-Gable…
There are many factors to consider in raisin grape production. Read More
Grapes
December 29, 2015
Employing Sheep For Weed Control
Sheep can help control weeds, but they do more than that. According to Chris Benziger, who has been employing sheep Read More
Grapes
December 29, 2015
Digital Mapping Could Help Growers Impro…
The Lake Erie Regional Grape Program is leading a $6 million USDA Project in precision viticulture, giving grape growers access to digital maps detailing the health of their vineyards. Read More
Grapes
December 28, 2015
Going For The Green – California W…
California grower/consultant earns medal for community and employee relations. Read More
[gravityform id="62" title="false" description="false"]