This situation should correct itself when growth returns to normal. Therefore, do not apply extra fertilizer to correct low tissue concentrations in a situation of vine overgrowth. Review the vine growth and crop load from current and last season. Choose the combination of tissue analyses and crop growth listed below that corresponds to your situation. Follow the instructions given for the appropriate category.
Low tissue analyses and abundant vine growth.
If vine growth is luxurious, don't apply additional fertilizer. Low tissue analyses and weak vine growth. If vines are weak, discolored, or stunted, apply fertilizer at rates recommended by your local Extension Service. Normal tissue analyses and vine growth. If your tissue analyses are within the normal range, continue with your current fertilizer program.