EFFECTS OF NUTRITENTS AND LIGHT EMITTING DIODE (LED) ON GROWTH OF LOLO AND GREEN OAK LEAF LETTUCE HYDROPONIC

Abstract

Lettuce is one of the most popular vegetables. It is often used like salads without boiling so hydroponic methods will overcome bug and parasite problems in the soil. In this study, we used two hydroponic systems called Deep Water Culture (DWC) and Nutrient Film Technique (NFT) to grown two lettuce species, lolo lettuce Lactuca sativa var. Lollo rosso and green oak leaf lettuce - Lactuca sativa var. crispa. The results showed that the suitable nutrient was Howard (N(NO3-): 1433.5ppm, P2O5: 500 ppm, K2O: 2100 ppm) and red, white, blue LED also effected on the growth of two lettuce varieties. We reached the highest lettuce yield (a fresh weight of 260 g/plant) with a 4-lamps red LED system (25W, 220V, 30 µmol/m2/s, 16000 lux) using NFT. On the other hand, the 4-lamps white LED system (16W, 220V, 20 µmol/m2/s, 14000 lux) and the 4-lamps blue LED system (25W, 220V, 32 µmol/m2/s, 19000 lux) that have a constant distance between the lamp and the plant also reached the high yield with a fresh weight of 222 g/plant. The nitrate content in lettuce ranges from 1050.06 to 1225.25 mg/kg, this value is allowable level of WHO.