The effect of four commercial substrates in polystyrene trays with 200 and 288 cells, was evaluated on the production of seedlings of lettuce (Lactuca sativa cv. Vera) in a plastic greenhouse, from 15/01 to 13/02/03, in Campinas, São Paulo State, Brazil. The treatments consisted of factorial combinations of four commercial substrates (Plantmax HA, Hortimix folhosas, Golden Mix 47 and, Vida Verde Tropstrato hortaliças) and two cell sizes (200 and 288 cells). The experimental design was a randomized complete design, with the plots split with each part subdivided for the evalution time, with three repetitions, each beign made up of a tray. At 5; 10; 15 and 20 days after germination, twenty random plants from each plot were evaluated for their stem height, number of leaves, clod stability of substrate and foliar area. Fifteen and twenty days after germination, the lettuce seedlings grown in Plantmax presented better development characteristics than other substrates. Seedlings produced on trays with 200 cells presented greater number of leaves and bigger leaf areas than those produced on 288 cells trays.
Lactuca sativa L.; commercial substrate; polystyrene tray
