Petiole sampling at bloom helps determine vine nutritional needs. Sample the leaf petioles opposite flower clusters.
General nutrition links:
- Grapevine nutrition-Pete Christensen's powerpoint gives deficiency symptoms, tissue levels, and correction recommendations.
- Use of Tissue Analysis - Instructions for how to sample petioles and reference tissue levels.
- Nutrition information on the Integrated Viticulture website.
- Mineral Nutrition and Fertilization - Chapter from the Raisin and Table Grape Production Manual.
- Vineyard nutrient needs vary with rootstocks and soils.
- Selected Commercial Laboraties in Northern California
Boron:
- Fall foliar sprays prevent Boron deficiency symptoms in grapes. 2006 California Agriculture.
- Drip irrigation can effectively apply Boron to San Joaquin Valley vineyards. 2005. California Agriculture.
- Boron deficiency in California vineyards. 1960. American Journal of Enology and Viticulture.
- Boron deficiency in grapes. Summarized from “Grapevine nutrition and fertilization in the San Joaquin Valley.”
Magnesium:
- Magnesium Deficiency Becoming More Common. UC Cooperative Extension Tulare County
Phosphorus:
- Managing phosphorus deficiency in vineyards. 1999. Practical Winery and Vineyard.
Zinc:
- Grapevine response to concentrate and to dilute application of two zinc compounds. 1978. American Journal of Enology and Viticulture.
Grape Nutritional Deficiency Images courtesy of Pete Christensen
Click on an image for a closer view and to scroll through the pictures.
B def Merlot leaves
K def Cab franc
P def Cab Sauv.
Mg def Zinfandel