Influence of Substrate and Supplementary LED lighting on Vertical Farming of Basil (Ocimum basilicum L.) and Pak Choi (Brassica rapa var. chinensis)

Abstract

Application of “plant factory” concept in protected culture is gaining momentum due to its technological and economic merits in many countries. This research examined the plant growth and yield of vertically grown pak choi (Brassica rapa var. chinensis) (in nutrient film technique (NFT) culture) under supplementary lighting with two different combinations of blue to red color LEDs (1:9 and 1:2 ratios) in comparison with horticulture grade and non-horticulture grade (recommended for general use) white (full spectrum) LED while keeping sunlight as the control treatment. Meanwhile NFT culture was compared to plant growth, yield and nitrate accumulation of basil (Ocimum basilicum L.) in comparison with conventional soil, culture and compost mixed coco-peat substrate in a replicated trial, conducted under greenhouse conditions with intensive micro climate control. A significantly high vegetative growth and total to yield could be found in the NFT grown basil. The nitrate accumulation in basil leaves was well below the maximum permissible limit (MPL), set-fourth by the recommendations of the European Health Commission. Meanwhile, the highest overall leaf quality of pak choi was achieved by the normal LEDs. Horticulture graded to LED maintained fairly high chlorophyll a and b contents contributing to its characteristic leaf color.