Nitrogen and calcium nutrition of Petunia × hybrida ‘Coral Sea’

The effects of N and Ca nutrition on plant growth and shoot elemental content of Petunia × hybrida Hort. Vilm. - Andr. ‘Coral Sea’ were evaluated. Nitrogen and Ca were applied separately or in combination in three experiments: (1) N at 0, 100, 200 or 400 mg l−1; (2) Ca at 0, 75, 150 or 300 mg l−1; (3) N at 0 or 100 mg l−1 and Ca at 0 or 150 mg l−1 combined factorially. Shoot and root dry weights, branch length and flower number were highest when plants received 100 mg l−1 N. Plants treated with 150 mg l−1 Ca had the highest shoot and root dry weights. Branch length was maximal at 300 mg l−1 Ca. Nitrogen and Ca interacted to increase shoot dry weights, branch number and length, leaf area and flower number. Increasing N concentrations increased N and decreased P, Mn and Zn shoot contents. Calcium content of shoots increased while N, P and Mg decreased in response to increasing applications of Ca to petunia plants. Minimal N and Ca tissue concentrations for optimal P. × hybrida growth were 3.3 and 0.67%, respectively.