• Phosphorus-deficient plants have weak roots, are stunted, and produce small, dark, dull, graygreen leaves .
  • The oldest leaf, at the base of the shoot, turns bright yellow .
  • However, unlike nitrogen deficiency, the leaf directly above this leaf remains dark green.
  • . Brown patches appear between the veins on mature leaves.
  • These become scorched and spread until the leaf dies prematurely.
  • Fruit set is reduced, so production is impaired until the deficiency is corrected.