The levels of electrical conductivity (EC) can alter water and nutrient uptake by plants, influencing their metabolism and yield. This experiment was carried out to verify the effects of EC on the yield and the development of the crisp head lettuce cv. Ryder in hidroponics. The tendency of the electrical conductivity changes of the nutrient solution during the development of the lettuce was also evaluated. A completely randomized design was used, with six replications and three treataments: EC1= 1.46, EC2= 2.46 and EC3= 4.21 (± 0.24) mS cm-1. Lettuce head diameter and height, and root dry weight were not influenced by EC. The largest fresh and dry weights of heads were obtained for 2.46 (± 0.24) mS cm-1. All treatments had the same tendency of reducing EC during lettuce growth.
Lactuca sativa; nutritive solution; yield; soilless culture