Volume of cells on trays influences hydroponic lettuce production

Abstract

Lettuce seedlings used on hydroponic cultivation (NFT) are usually produced in trays with small volume, requiring two transplants: from tray to nursery and then to the definitive place. The aim of this study was to verify lettuce performance under NFT system, using seedlings produced in trays with several cell volumes (50, 40, 35, 31, 30, 29, 27, 20 and 10 cm³ cell-1). The tray volumes are considered treatments. The experimental design was completely randomized blocks, with four replicates. Seedlings were transplanted directly to the definitive profile, except those ones produced in 10 cm³ cell-1. Two harvests were performed, at 22 and 29 days after transplant (DAT). We evaluated number of senescent leaves, total number of leaves, shoot fresh mass, root fresh mass, shoot dry mass, stem length and productivity. The best performance was obtained using seedlings produced in trays with higher volume per cell. The nursery phase was not necessary and it was possible to obtain reduction from two to one transplant, corresponding to trays of 20 to 50 cm³ cell-1. Seedlings produced in trays with 40 and 50 cm³ cell-1 made the early harvest possible, at 22 DAT of cultivation under hydroponic NFT system.