Authors: Annie Klodd and Anne Sawyer, University of Minnesota Extension

Key Points:

1. Minimize the amount of nitrogen applied in the fall; save it for the spring.
2. Granular fertilizer is best applied as a broadcast directed to the vine rows
3. If possible, avoid fertilizer application to the grassy aisles unless groundcover renovation is the intent
4. Fertilizer application rates should be calculated based on soil and foliar tests. Use test reports from the current year or recent years.

During the growing season, grapevines allocate significant amounts of sugars and nutrients to the fruit, which is then removed from the vineyard when the fruit is harvested. If the soils are limited in nutrients like phosphorus (P), potassium (K), nitrogen (N) and magnesium (Mg), adding these nutrients back into the soil periodically is important to the continued productivity of the vineyard. Fertilizer amounts (rates) applied should be calculated based on soil and foliar test results, rather than applying an arbitrary rate.