Brian A. Krug

GERANIUM LEAF TISSUE NUTRIENT SUFFICIENCY RANGES BY CHRONOLOGICAL AGE

Two cultivars of geranium (Pelargonium × hortorum) were grown under five different fertilizer regimes, 50, 100, 200, 300, or 400 mg·L−1 nitrogen (N). The two cultivars were chosen to represent a dark-colored leaf cultivar, ‘Tango Dark Red’ and a light-colored leaf cultivar, ‘Rocky Mountain Dark Red’. Tissue samples were collected and analyzed for the content of 11 elemental nutrients every two weeks for a period of 12 weeks. The dark-colored leaf cultivar contained higher nutrient concentrations, with the exception of magnesium, sulfur, iron, and copper, than the light-colored leaf cultivar. Compared to concentrations previously published for geraniums, concentration ranges observed in this study were narrower. In addition, this study accounted for differences in concentrations over the entire crop cycle and reflects levels associated with current fertilization practices.