Nitrogen fertilization in the nursery: effect on strawberry tray plant yield and performance

The quantity and timing of nitrogen application during flower initiation and differentiation and its subsequent effect on plant performance and fruit quality was examined in June-bearing cultivars; ‘Ritmo’ and ‘Malling Allure’. During vegetative growth, flower initiation and flower differentiation two rates of nitrogen (N), 160 and 225 kg N ha^‑1 were compared. N-application was kept low during natural long days (July-August) and was increased during flower differentiation from mid-September until November. Following cold storage, the tray plants were grown in containers on substrate and data relating to fruit number, fruit size, fruit shape and yield were collected. Extra early N application in August during the nursery period resulted in more stolon development plant^‑1 the following year in ‘Malling Allure’, however, in ‘Ritmo’ the timing and rate of N application had no effect on runner formation. Higher and later N application delayed harvest particularly in ‘Ritmo’ (6 days), however, the same effect was not observed in ‘Malling Allure’. The timing and rate of N application did not affect fruit shape in either cultivar. Later application and higher N rates increased total fruit number. In ‘Ritmo’ flower trusses became more complex in architecture and the typical concentrated ripening time for this cultivar resulted in a smaller average berry weight. Due to its typical simple dichasial truss structure the fruit size of ‘Malling Allure’ was not affected.