Effect of medium size and compost dose on organic red lettuce (Lactuca sativa L. Var red rapids) cultivation in pots

Small-scale urban farming business of organic vegetables was emerging in some locations of Indonesia.  The study aimed to observe the effect of medium size and organic compost dosage on the growth and yield of red lettuce (Lactuca sativa L. var red rapids). A pot experiment was arranged in a completely randomized design (CRD) with a 3 x 4 factorial treatment using 3 replicates. Treatment consists of two factors namely medium size and organic compost dosage. The media size consisted of three levels: 1kg (S1), 3kg (S2), and 5kg (S3). The dosage of organic compost consisted of 4 levels: 0% (D0), 10% (D1), 30% (D2), and 50% (D3). The study was conducted in a plastic house, using a clay texture of subsoil and organic compost made from a mixture of cattle manure, chicken manure, MSG industrial waste sludge, coconut husk dust, oil palm empty fruit bunches (EFB).  Some growth and yield parameters including water consumption and water productivity were considered. Results showed that red rapid lettuce growth was depressed at 1kg and 3kg medium sizes and growing more freely at 5kg medium size.  Three best yields of 75.3g, 65.7g, and 90.0g per plant were performed by the treatment combinations of 3kg medium size-10% compost dose, 3kg medium size-30% compost dose, and 5kg medium size-50% compost dose.  The treatment combination of 3kg medium size-10% compost dose, however, could be considered as the most optimum treatment combination since it used the least amount of medium and compost although the plant experienced in restricted growth.