304 Effects of Calcium and Magnesium on Growth, Fruit Yield, and Quality of Greenhouse Tomato Grown in Rockwool

Summary

Tomato (Lycopersicon esculentum Mill.) cv. Trust was grown in rockwool in summer and fall 1999 and 8 calcium/magnesium nutrient treatments, formed by two levels of calcium (Ca: 150 and 300 ppm) and four levels of magnesium (Mg: 20, 50, 80, and 110 ppm), were applied to investigate the effects on growth, fruit yield and quality. High calcium (300 ppm) increased overall fruit yield and size, reduced incidence of blossom-end rot and fruit cracking. However, high calcium also reduced the dry-matter content, soluble solid content and firmness of tomato fruit, and increased fruit russetting. Magnesium did not affect early growth or fruit production. However, 2 months after applying the treatments, the plants grown under 20 ppm Mg started to show Mg-deficient symptoms (leaf chlorosis), and Mg-def