Dr. Monica Ozores-Hampton
Vegetables are only able to access individual nutrients at a specific pH levels. The most aligned pH for all nutrients being accessible is a pH of 6.0 to 6.5. At a pH higher or lower than 6.0 to 6.5, the plant has difficulty absorbing nutrients, even if you over-fertilize.
NITROGEN. Vegetables require 3.0–6.0%. In general, OLDER/lower leaves suffer first. Signs include yellowing of older leaves with reddish undersides. Nitrogen tends to detain growth and accelerate flowering, however yields will be reduced.
PHOSPHORUS. Vegetables require 0.2–0.7%. In general, OLDER/lower leaves suffer first. Signs include stunted growth, thin stems, brown/dead spots. Plants tend to be darker green. Leaves of tomato, lettuce, corn and brassicas can have a purple pigment to the underside of leaves.
POTASSIUM. Vegetables require 2–5%. In general, OLDER/lower leaves suffer first. Signs include tip burn and brown/dead spots between the main veins. As the deficiency progresses, only the veins remain green and the leaves tend to curl.
CALCIUM. In general, NEWER leaves suffer first. Lack of calcium causes blossom end rot on tomatoes.
MAGNESIUM. Vegetables require 0.15–0.4%. Signs include advanced yellowing with brown/dead spots developing.
BORON. Signs include slight yellowing and death of terminal bud.
IRON. In general, NEWER leaves suffer first. Signs include leaves on the TOP of the plant are yellowing between the veins at the base of the leaf. Leaf can look bleached and have brown/dead spots.
MANGANESE. Signs include yellowing between the veins. As deficiency progresses, leaves get a gray metallic sheen with dark brown/dead spots along the veins. There is no signs on the underside of leaves.
SULFUR. Overall yellowing of entire plant. Veins and leaf stalks have a reddish/pinkish color on underside. Advanced deficiency also has brown/dead spots on leaf stalks and leaves become erect and often twisted and brittle.
ZINC. Younger leaves yellow between the veins first, then intense yellowing between the veins occurs. Often leaves become small and take on a rosette-like appearance.
Visual Nutrient Deficiency App. is available at:
www.yara.com/media/apps/checkit/
