Electric conductivity and space between plants on baby leaf production in NFT hydroponic system inside greenhouse

The baby leaf market is at its beginning in Brazil. Similar to the market, production systems are starting to be established. Thus, they need to be studied in order to gain knowledge of how to produce baby leaf in each production system. In Europe and in the United States, crops are cultivated in soil with mechanization due to the high amount of seeds used per hectare. In Brazil, production in soil is not yet used. Some farmers who grow leafy vegetables in nutrient film technique (NFT) hydroponic system are adapting their systems to grow baby leaf, but without the technical support provided by research. Therefore, in order to find answers on how to produce baby leaf in NFT hydroponic systems, the objective of the present study was to verify the effect of nutrient solution electrical conductivity (0.4, 0.8, 1.2 and 1.6 mS cm^-1) and the space between plants (2.5, 5.0 and 10.0 cm) on the development and yield of watercress and rocket salad. The experiments were carried out in a nutrient film hydroponic system inside a greenhouse in the period from March to June 2012. The experimental design used was split plot with randomized blocks replicated four times. The harvest was carried out when the leaves of each species reached length of approximate 15.0 cm. There was no significant interaction among treatments; however, there were statistical effects for the treatments separately. The bigger yields of 4.1 and 3.3 kg m^-2 were obtained at 1.6 mS cm^-1 for watercress and rocket salad, respectively. A spacing of 2.5 cm resulted in the highest yields, particularly 5.9 and 4.0 kg m^-2 for watercress and rocket salad, respectively.