Role of Boron in Tomato Production

Boron is involved in the production of nucleic acid and plant hormones, the movement of plant sugars, and in carbohydrate metabolism and translocation.

Boron effect at growth stages

Stage Boron effect
Establishment Ensure good shoot growth
Vegetative Growth Ensure growth is not limiting
Flowering - Fruit Set Maximize flower set, development and fruiting
Fruit Ripening - Maturity Ensure even ripening
See more on Tomato Growth Stages.

General guidelines for Boron application

Boron deficiency prevents root growth and disrupts cell membranes, which has a direct effect on plant’s uptake mechanism. On the other hand, excess boron can block the transportation of calcium, so it is important that accurate application rates are adhered to. Boron accumulates in the leaf margins, turning them black. Root death occurs where levels are particularly high. Soils with high levels of boron can be ameliorated by leaching.

Boron deficiencies in Tomato

In cases of severe deficiency, the growing points of the main shoot and laterals die and the crop is lost. The younger leaves remain small, are curled inwards and become deformed. They have chlorotic spots between the veins, which are yellow to orange – a most striking feature – and the veins themselves can become yellow or purple. The older leaves appear yellowish green. The petioles are brittle and break off suddenly, leading to lower yield. Roots are short, with thickened, necrotic tips. Fruit becomes unmarketable because of their cracked or corky lesions that may resemble wind rub. Fruits may also show an ‘internal browning’ or blotching.

See more about boron and other nutrients deficiencies in tomatoes on Tomato Crop Nutrition.