Controlled-release compound fertilizers improve the growth and flowering of potted Freesia hybrida

Abstract The controlled-release fertilizers (CRFs) are the fertilizers which gradually release their mineral nutrients, while at the same time providing proper nutrition to the plants. The CRFs have been widely used to improve crops’ quality and quantity, but have not been applied on Freesia hybrida so far. In this study, Freesia ‘Shangnong Ruxiang’ was used to determine the effect of CRFs on its vegetative and reproductive growth. Two different kinds of commercial CRFs i.e. Osmocote Classic and Agroblen were applied in various doses. In an appropriate dose, Osmocote Classic and Agroblen improved the growth of Freesia . The overall effect of Agroblen is better than Osmocote. Under treatments of 5 g/L Osmocote and 5 g/L or 7 g/L Agroblen, the plant height, scape height, scape number, scape strength, and chlorophyll content were higher than other groups. Under 7 g/L Agroblen, the plants blossomed 10 days earlier than that of control. Taken together, 5 g/L of Osmocote and 5 g/L or 7 g/L of Agroblen are recommended for strong leaf and corm growth with good flowering phenotype, while 5 g/L or 7 g/L of Agroblen only is optimum for early flowering in Freesia .