Nutrient Deficiencies

Nitrogen: The growth rate of nitrogen-deficient cucurbits is reduced and a general yellowing of the plant occurs, beginning at the oldest leaves. Cotyledons and older leaves die and younger leaves stop growing. Cucumber fruit are more slender and pinched at the blossom end. Cantaloupe fruit are small, light-colored and thin-skinned with small seeds.

Phosphorus: Deficient plants grow slowly, internodes are shortened and stunted. Typically leaves show a purplish color. . Phosphorous-deficient cucurbits produce poor quality flowers, and fruit- and seed-set are reduced.

Potassium: Young leaves on potassium-deficient plants are small, dull-appearing and assume a cupped appearance. Leaves develop peripheral chlorosis, which eventually becomes interveinal. Cucumber fruit are often narrow at the stem end, giving fruit a club-shaped appearance. Cantaloupe fruit develop gritty flesh and a bitter taste.

Magnesium: Near the end of the growing season, older leaves develop interveinal chlorosis which initially appears at leaf margins and progresses inward. Eventually entire leaves become necrotic. Because magnesium deficiency develops late in the growing season, fruit yield is generally not reduced significantly.

Iron: Young leaves develop interveinal chlorosis while older leaves remain green. This is due to iron’s lack of mobility in plants.

Calcium: Growth is retarded and intermodes are shortened. Leaf margins stop expanding and leaves cup downward. New root growth is impaired. Blossom end rot of the fruit may occur.

Manganese: Interveinal areas of leaves become chlorotic. Deficiencies can be induced by over-liming.

Boron: Leaves become chlorotic and then necrotic, with death to the growing point. Fruit quality is decreased.

Molybdenum: Symptoms similar to nitrogen deficiency. Plants are stunted. Leaves develop marginal and interveinal chlorosis which may lead to a scorched appearance.

Highly acid or alkaline soils often lead to major and minor element deficiencies. Excessive or unbalanced use of fertilizers may also result in some micronutrients becoming unavailable to the plant.

Use a balanced fertilizer program appropriate to the soil and to the crop. Nutrient sprays can help correct many of the minor element deficiencies. Altering soil pH can often eliminate deficiency or toxicity problems.