Nutrient charge, composition of media and nitrogen‐form affect growth of vinca

Abstract

Growth of vinca [Catharanthus roseus (L.) G. Don ‘Grape Cooler'] was compared under several cultural conditions. Conditions investigated included two types of media (a peat‐lite mix and a mix containing 25% pine bark) and five types of nutrient charges in the peat‐lite media (sulfated micros, chelated micros, sulfated or chelated micros with pH adjustment to 5.5, and no charge). Nitrogen (N) source effect on growth was also investigated. Plants were grown at five different ratios of nitrate‐N to ammonium‐N. Greatest growth as measured by shoot length and shoot dry weight occurred in the peat‐lite media at either the sulfated micro or chelated micros adjusted to pH 5.5 and at the highest ratios of nitrate‐N to ammonium‐N. Root dry weight and growth were negatively affected by high levels of ammonium‐N in the fertilizer solution.