The effect of light intensity and duration on yield and quality of everbearer and June-bearer strawberry cultivars in a LED lit multi-tiered vertical growing system

This study aimed to provide insights into the efficient use of supplementary lighting for strawberry crops produced in a multi-tiered LED lit vertical growing system, ascertaining the optimal light intensity and duration, with comparative energy use and costs. Furthermore, the suitability of a premium everbearer strawberry cultivar with a high yield potential was compared with a standard winter glasshouse June-bearer cultivar currently used for out-of-season production in the UK. Three lighting durations (11, 16 and 22 h) provided by LEDs were combined with two light intensities (344 and 227 µmol) to give six light treatments on each tier of a three-tiered system to grow the two cultivars. The everbearer showed a higher yield with a higher correlation with increased lighting and a greater proportion of reproductive growth than the Junebearer. Light intensity and duration increased yield with duration also increasing sugar content (°Brix). However, even with yields of over 100 t ha^‑1 recorded in this study, yields are likely to be insufficient to cover the cost of electricity.