Fruit vegetables in indoor farming - potential of chili pepper production

In order to reach profitability of indoor vertical farms the available plant species have to expand to include higher-quality plants such as fruit, fruit vegetables and plant raw materials. The aim of this work was to investigate the effect of different LED spectra and also photoperiods on the growth and quality of a dwarf chili pepper (Capsicum annuum) in a multilayer system, while considering the resource use efficiency. Plants were grown in 100 days in two consecutive experiments with three different LED spectra (red/blue, white, white+UV400nm) at 300 mu mol m(-2) s(-1) and increasing photoperiods (20, 24, 26 h) at the same DLI of 21 mol m(-2) s(-1). The used cultivar was characterized with a suitable growth height of 20-27 cm. The used spectra showed no effect on the growth or fruit quality. The share of damaged fruits was in all treatment with 1% very low. The fruit yield was with 35% significantly increased in white+UV400nm, reaching a surface use efficiency (SUE) of up to 30 kg m(-2) a(-1). The target of increasing the light energy use efficiency (EUE) at a longer photoperiod but same DLI, was not confirmed. An increase of day length to 30 h was also not advantageous. The study highlights the potential of vertical farming for a consistent production of chili pepper.