Generally iron deficiency does not decrease growth of lettuce. Only inner leaves are affected, because symptoms of iron deficiency always start on youngest leaves. They show yellow green, later lemon yellow and pale yellow interveinal chlorosis. Main veins still remain green. With strong deficiency veins become chlorotic, too and necrotic areas appear near leaf margin.
Only severe deficiency produces symptoms on older leaves. Potentially brown necrosis turns up on margins of chlorotic leaves and spreads over whole leaves.
Iron deficiency
Symptoms of iron deficiency always start on youngest leaves. They show yellow green, later lemon yellow and pale yellow interveinal chlorosis. Main veins still remain green. With strong deficiency veins become chlorotic, too and necrotic areas appear near leaf margin.
Only severe deficiency produces symptoms on older leaves.
Roots are short and brownish. Very many secondary roots arise.
Iron deficiency
With iron deficiency roots are shorter than normal. They show brownish discoloration. Furthermore very many secondary roots arise.
Iron deficiency on roots