Grapevine nutrition is a critical factor impacting the health of the vine, the quality of the wine and the environment. Yeast assimilable nitrogen content (YANC) plays a critical role in the unfolding of an uninterrupted fermentation process; at the same time there is concern about the potential of excessive nitrogen leaching into the environment. Getting recommendations on timing and application rates are critical for both the environment and the quality of the end product. Other nutrients such as Potassium, Boron, Zinc, etc. play an important role in a number of metabolic processes in the plant. They can affect yield, berry composition (and thereby wine quality) as well as winter hardiness. Extreme winter temperature fluctuations and very low minimum temperatures are the biggest factors affecting yield reductions in some vintages.