Innovative harvest practices of Butterhead, Lollo rosso and Batavia green lettuce (Lactuca sativa L.) types grown in floating hydroponic system to maintain the quality and improve storability

•Harvest practice significantly affected storage life, fresh weight and visual appearance of lettuce.•Rooted lettuce may be stored at 4-5 °C for longer without any decline in quality.•Nitrate content of the FHS grown lettuces was below the limits set by the E.C.•Rooted harvest preserved freshness providing practical advantages to commercial handling.

In series of trials, we evaluated the effects of different harvest practices and storage conditions in postharvest quality of lettuce (Lactuca sativa L.) types of Lollo rosso (cv 'Carmesi'), Butterhead (cv 'Gemmaverde') and Batavia green (cv 'Dragone') grown in floating hydroponic system (FHS). There was clear indication that harvest practice significantly affected storage life (SL), relative fresh weight (RFW) and visual appearance rating (VAR) of all lettuce types. SL of rooted plants increased by up to 20.8, 16.6 and 26 days for cvs 'Carmesi', 'Gemmaverde' and 'Dragone', respectively compared to the un-rooted controls (conventional harvest). Independently to cultivar tested, the RFW values of rooted plants, ranged from 96.86 to 113.77%, while those of the un-rooted controls from 79.06 to 87.51%. Leaf color and chlorophyll degradation was not affected or changed in rooted plants, even after 28 days at storage. We propose that rooted plants can be stored at temperatures of 4-5 °C for longer without any quality decline, thus giving practical advantages to commercial handling.