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Lettuce is the most important leaf vegetable grown in Argentina mainly in the green belts. This species requires 90 to 100 kg ha-1 nitrogen, which can be supplied by synthetic chemical fertilizers or organic supplements. The objective of this work was to evaluate the effect of the application of vermicompost on the growth parameters of lettuce in two commercial types: leaf lettuce (cv Brisa) and butterhead (cv Daguan). Seedlings were produced in plastic trays and were transplanted when two leaves were completed expanded 30 days after sowing after that management was similar to a commercial one. The experimental design was a randomized complete block with four replications. During cultivation and at harvest measurements of fresh and dry weight, leaf number and area, nitrate and reducing sugar concentrations were made. Calculations for yield were performed. At harvest, vermicompost addition affected nitrate content in leaf lettuce (cv Brisa) increasing its concentration. Yield was not affected by vermicompost application.

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Horticultural crops have a strong impact on human nutrition. Lettuce is the most important leafy vegetable in Argentina and it is cultivated mainly in green belts, in greenhouses or open field. The aim of this study was to evaluate growth and phytonutrients concentration of leaf lettuce under greenhouse and field production. Crop establishment was made from seedlings produced in a commercial greenhouse. Loose lettuce cv. Brisa was used for field and greenhouse growth. Experimental design with complete random block with 4 replicates per treatment was used. Fresh and dry weights of shoot, number of leaves, color, ascorbic acid, chlorophyll content were measured. Absolute and relative growth rate and commercial yield were calculated. Lettuce grown under greenhouse system showed, as expected, a higher value of fresh and dry weight, number of leaves, leaf area, yield and absolute and relative growth rate. Ascorbic acid value of the leaves decreased during lettuce growth in both production systems. Chlorophyll content was higher in the greenhouse cultivation but the antioxidant capacity was lower in lettuce leaves from greenhouse than the leaves grown on open field.