The hydroponic system is very often used for greenhouse plant production. Flood irrigation on benches or on flood floors is applied in the production of vegetable transplants and ornamental plants. Since fertigation is used in a closed system using the recirculation of a nutrient solution, this system is environmentally friendly. The aim of the research conducted in 2012-2014 was to determine the effect of flood fertigation with nutrient concentrations of EC 1.0, 2.0, 3.0 and 4.0 mS cm‑1 on the quantity and quality of leaf lettuce cv. Locarno grown in different substrates: coconut coir, peat and rockwool. The experiment was conducted on the flood floor of a greenhouse in the spring. The effects of the tested concentrations of the nutrient solution and the growth substrate on crop yield and quality were assessed by measuring the weight of lettuce heads and the nitrate content in them. The highest total and marketable yields and the heaviest heads were obtained from cultivation in rockwool. Also recommendable was the coconut coir substrate, in which, at the solution concentration of EC 2.0 mS cm‑1, the lettuce plants produced a high marketable yield of good quality heads with a low nitrate content. An increase in the concentration of the solution caused the nitrate content in lettuce heads to increase, and at EC 3.0 mS cm‑1 the nitrate levels exceeded the permissible limit. The highest nitrate content was found in the crop grown in rockwool, and the lowest in coconut coir.  

24.1.2019