Nitrogen, Potassium and Magnesium Nutrition of Three Orchid Genera1

Abstract In nutrient culture, growth of hybrid plants of Cymbidium and Phalaenopsis was optimal with 100 ppm N, 50-100 ppm K and 25 ppm Mg and optimal for Cattleya with 50 ppm each of N, K and Mg. Cymbidium plants developed N deficiency symptoms when supplied with 50 ppm N. K levels tested had little effect on growth responses. Mg at 100 ppm decreased growth of all 3 genera in comparison to 50 ppm.