It may be possible to bring the vines into full production one year earlier with fertigation. If you are interested in fertigation, contact your Extension engineers and horticulturist via your local county Extension office. Soil pH should be checked every two to three years to determine if lime is needed. If lime is necessary, it is important to use the dolomitic form since grapes have a high requirement for magnesium. Magnesium deficiency, which shows up later in the season, is of concern to muscadine producers since in severe cases the fruit may shatter prematurely.
Symptoms are a yellowing between the veins of older leaves.
The yellowing progresses up the shoots as the leaves grow older. 21.1 Magnesium deficiency of muscadine showing yellowing between the veins. If magnesium deficiency is evident and the soil pH is too high to add dolomitic lime, use a soluble form of soil applied magnesium. Young vines can be treated with about two ounces of soil applied magnesium sulfate per vine to correct magnesium deficiency. Occasionally, it is necessary to apply boron in some vineyards to realize maximum yields, since boron deficiency can cause poor fruit set.