Efficiency of the floating system in the production of lettuce seedlings using different trays and concentrations of nutrient solution

The quality of seedlings is a determining factor to guarantee the greatest potential crop productivity. The aim of this study was to evaluate the quality of lettuce seedlings grown in floating system, in relation to cell volume and electrical conductivity of the nutrient solution. The experiment was carried out in a completely randomized design, in a 3 x 2 x 4 factorial scheme, with three replicates. Seedlings of three lettuce cultivars (Great Lakes 659, Elba and Creta) were produced in two types of trays (128 and 200 cells) and fertigated with nutrient solutions (four electrical conductivities of 1.0; 1.5; 2.0 and 2.5 dS/m). The variables evaluated were: height, number of leaves, length of the main root, stem diameter, leaf area, total dry mass and shoot dry mass/roots dry mass (MSPA/MSR) ratio. Great Lakes 659 showed more vigorous seedlings for most of the evaluated variables. The three cultivars produced higher quality seedlings when cultivated in trays with 128 cells, with the EC of the nutrient solution ranging from 1.8 to 2.0 dS/m.