The aim of the study was to determine the impact of dead organic mulches (unprocessed sheep wool - SW and ecological wool - EW), black polyethylene film (PE) and unmulched soil (WM) on the moisture regime of Hortisol and the yield of lettuce cv.'Melina'.The research was carried out at an trial field at the Faculty of Agriculture in Zagreb from April to June 2017. The experiment was set out according to a randomized block design with three replications. Soil samples were taken decadally from depths of 0-10 cm and 10-20 cm, in 3 replications, and the soil moisture content was determined by gravimetric method. The current moisture content in the soil was significantly influenced by: days after transplatation lettuce to open field (DAT) and mulch (M). The significantly low values of soil moisture were determined at 46 DAT, and high at 5 DAT. Considering the mulch, the soil moisture in both layers as follows: PE SW EW WM. Diameter of the lettuce rosette was not significantly affected by the mulch type. Lettuce rosette, grown on SW (20.7 cm) was significantly higher compared to PE (18.4 cm), EW (18.0 cm) and WM (17.8 cm). The highest marketable yield of lettuce was achieved when wool mulch was applied (6.58 kg/[m.sup.2] on EW, ie 6.56 kg/[m.sup.2] on SW), and the lowest under PE (4.60 kg/[m.sup.2]). Woolen mulches have proved to be a good alternative to the previous application of PE mulches. Keywords: Lactuca sativa L., polyethylene film, sheep wool, soil moisture, yield Cilj istrazivanja bio je utvrditi utjecaj mrtvih organskih malceva (nepreradena ovcja vuna - SW i "filcana" ekoloska vuna - EW), crnog polietilenskog filma (PE) i nemalciranog tla (WM) na rezim vlaznosti hortisola i prinos salate kultivara 'Melina'. Istrazivanje je provedeno na pokusalistu Agronomskog fakulteta u Zagrebu u razdoblju od travnja do lipnja 2017. godine, a pokus je postavljen prema slucajnom bloknom rasporedu u tri ponavljanja. Uzorkovanje tla obavljeno je dekadno sa dubina 0-10 cm i 10-20 cm, u 3 ponavljanja, a sadrzaj vlage u tlu odreden je gravimetrijskom metodom. Na sadrzaj trenutacne vlage u tlu statisticki su znacajno utjecali: dani nakon presadivanja salate na otvoreno (DAT) i malc (M). Statisticki najnize vrijednosti vlage u tlu utvrdene su kod 46 DAT, a znacajno vise kod 5 DAT. S obzirom na vrstu malca,u oba sloja tla trenutacna vlaznost se kretala slijedecim redom: PE SW EW WM. Na promjer rozete salate nije znacajno utjecala vrsta malca. Rozeta salate uzgajane na SW (20,7 cm) bila je znacajno visa u odnosu na PE (18,4 cm), EW (18,0 cm) i WM (17,8 cm).Najvisi trzni prinos salate ostvaren je pod vunenim malcevima (6,58 kg/[m.sup.2] na EW, odnosno 6,56 kg/[m.sup.2]na SW), a najnizi pod PE (4,60 kg/[m.sup.2]). Vuneni malcevi pokazali su se dobrom alternativom dosadasnjoj primjeni PE malceva. Kljucne rijeci: Lactuca sativa L., polietilenski film, ovcja vuna, vlaga tla, prinos DETAILED ABSTRACT The lettuce cultivation technology in Croatia is still mainly based on the use of polymeric materials, especially black PE-film, so it is necessary to find and test new, environmentally friendly materials to achieve a satisfactory vegetable yields.The aim of the research was to determine the impact of dead organic mulches (unprocessed sheep wool - SW and eco wool -EW), black polyethylene film (PE) and unmulched soil (WM) on the moisture regime of Hortisol and the yield of lettuce (Lactucasativa L.) cv. 'Melina' in the spring-summer growing period (April-June). The research was conducted at the Faculty of Agriculture in Zagreb in 2017, and the experiment was set up according to randomized block design with three replications. Soil samples were taken decadally at depths of 0-10 cm and 10-20 cm, in 3 replications, and the soil moisture content was determined by gravimetric method in the laboratory. Sampling of plants to determine the most important economic characteristics of lettuce (mass, height and diameter of the rosette and market yield) was performed at technological maturity. The soil moisture during the lettuce vegetation did not drop below the wilting point at -1500 kPa (23.7% vol.). The soil moisture content was significantly affected by the days after transplatation the lettuce on the open field (DAT) and mulch type (M). The minimum moisture in soil was found at 46 DAT (25.13% vol. in 0- 10 cm layer and 26.54% vol. in layer 10-20 cm) and significantly high at 5 DAT (38.87% vol. in a layer of 0-10 cm or 37.74% vol. in a layer of 10-20 cm). With respect to M, at the depth of 0-10 cm, the highest soil moisture was measured under PE (35.18% vol.) and the lowest at WM (31.29% vol.), while differences in soil moisture between PE and SW (34.76% vol) were not significant. In the deeper soil layer significant differences were found between PE (35.34% vol.) and SW (34.19% vol.) in regards to WM (31.66% vol.), while a statistically significant difference between EW (33.51% vol.) and WM was not determined. In both layers, soil moisture was as follows: PE SW EW WM. The lettuce rossete diameter was not significantly affected by the type of mulch. The rosette of lettuce grown on SW (20.7 cm) was significantly higher compared to other mulch treatments (18.4 cm on PE,18.0 cm on EW and 17.8 cm on WM). The highest lettuce yield was achieved when wool mulch was applied (6.58 kg/[m.sup.2] on EW, 6.56 kg/[m.sup.2] SW) and the lowest on PE treatment (4.60 kg/[m.sup.2]). The best soil moisture conservation was acchieved under SW treatment. Also, the application of sheep wool as mulch in vegetable production has a bright future. Thus, sheep wool represents an promising substitute for the use of PE-film so far in the spring-summer growing period of lettuce, not only because of its exceptional hydro-regulatory properties, but also as a more environmentally friendly solution.