Grapevine Nutritional Problems - Q&A

Zinc deficiency.

Magnesium deficiency on a white grape cultivar.
If conditions are cold and wet  your vineyard it can have slow growth and all types of soil can show nutritional problems.

Vineyards on light sandy soil are naturally low in topsoil nutrients. The same is also true those with heavy clay soils which can become waterlogged at this time of year thus preventing nutrient uptake.

Magnesium deficiency.
We have attached pictures of the most commonly seen vineyard nutritional disorders - Zinc (Zn), Magnesium (Mg) and Iron (Fe).

Zinc disorder is often called little leaf because it affects shoot growth and grapevine leaf size (top). 
Iron deficiency.
Iron (Fe) deficiency shows up as pale leaves. This is often called lime induced chlorosis. This is due to the alkaline limestone rock underneath locking up iron and grapevines are not able to take iron up. Iron nutritional problems are generally fixed once the weather warms up and vine uptake increases.

Iron deficiency compared to healthy leaf.
Grapevines tend to show Potassium (K) deficiency when they are heavily cropped and maintenance applications of K have not been made in the vineyard. This shows up in mid- to late summer, where leaves may have a bronze color, especially on the west-facing side of the trellis. Some leaves may have dark spots or blotches.

Potassium deficiency.
We hope this sheds some light on the subject. If you have further questions why not take a picture and sent it to us?