Characterization of Pelargonium × domesticum nutrient disorders

B.E. Whipker, J.B. Henry, I. McCall
To produce regal geraniums (Pelargonium × domesticum), growers must be equipped with cultural information including the ability to recognize and characterize nutrient disorders. Two cultivars of regal geraniums were grown in silica-sand culture to induce, describe, and photograph symptoms of nutritional disorders. Plants received a complete modified Hoagland's all-nitrate solution of (macronutrient concentrations in mM) 15 nitrate-nitrogen (N), 1.0 phosphorus (P), 6.0 potassium (K), 5.0 calcium (Ca), 2.0 magnesium (Mg), and 2.0 sulfur (S) plus (micronutrient concentrations in μM) 72 iron (Fe), 18 manganese (Mn), 3 copper (Cu), 3 zinc (Zn), 45 boron (B), and 0.1 molybdenum (Mo). Nutrient-deficient treatments were induced with a complete nutrient formula minus one of the nutrients. The B-toxicity treatment was induced by increasing the element 10-fold higher than the complete nutrient formula. Reagent-grade chemicals and deionized water of 18 million ohms cm‑1 purity were used to formulate treatment solutions. We monitored plants daily to document and photograph sequential series of symptoms as they developed. Typical symptomology of nutrient disorders and corresponding tissue concentrations were determined. Symptoms of N, P, and S manifested early; therefore, these disorders may be more likely problems encountered by growers. Use of tissue concentrations and other diagnostic criteria about location on the plant and progression of the disorder can aid growers in diagnosing nutrient disorders of regal geraniums.
Whipker, B.E., Henry, J.B. and McCall, I. (2019). Characterization of Pelargonium × domesticum nutrient disorders. Acta Hortic. 1266, 49-54
DOI: 10.17660/ActaHortic.2019.1266.8
regal geranium, macronutrients, micronutrients, deficiency, toxicity

Acta Horticulturae