Effects of Plastic Mulch and Floating Cover on Lettuce Production in Sicily

The use of floating cover directly applied on top of the crop is rapidly increasing on leafy vegetables like lettuce as a simple, inexpensive and effective technique to induce earliness. Two lettuce types, ‘Iceberg’ and ‘Romaine’, under two different crop management systems (black plastic mulch and black plastic mulch combined with floating cover) were tested in Sicily in 2007. Plug type transplants were planted at the end of January on double rows. The nonwoven floating cover was applied after transplanting. Maximum and minimum air temperatures below the floating cover during the growing period were in the average 5 and 1.5°C higher than those without cover. Lettuces mulched and protected with floating cover reached their commercial fresh weight ten days before those without floating cover. Regardless of the cultivar tested, total yield was significantly higher in the plots where black mulch was combined with floating cover as compared to that obtained with black plastic mulch alone. Regardless of the direct covering, ‘Romaine’ was more productive than ‘Iceberg’.