A field experiment was conducted during the 2022 dry season to investigate the effect of organic manure and plastic mulch on soil water and thermal regimes and cucumber growth, yield and water use efficiency at the Teaching and Research Farm, Ekiti State University, Ado-Ekiti southwest Nigeria. The experiment was 2- factorial, laid out in randomized complete block design (RCBD) with four replications. The organic manure factor consisted of poultry, piggery and no manure while the mulching factor comprised black plastic mulch and no mulch. Soil water content and temperature of the 0 - 10 and 10 - 20 cm layers of the field were monitored while cucumber growth parameters, yield components and water use efficiency data were also collected. Soil temperature was significantly (p < 0.05) higher in mulch treatment compared to no mulch treatment in both 0 - 10 cm surface and 10 - 20 cm subsurface soil layers. Conversely, organic manure did not affect (p > 0.05) soil temperature although it was highest in no manure treatment. Mulching significantly (p < 0.05) increased soil water content while poultry manure treatment had the highest soil water content during the growing cycle. Mulching significantly (p < 0.05) increased the number of leaves, leaf area and vine length of cucumber. Both organic manure and mulching significantly (p < 0.05) influenced leaf temperature, number of fruits but not fruit length, fruit diameter, yield and water use efficiency. Furthermore, the combined application of plastic mulch and poultry manure gave the highest yield and water use efficiency of cucumber. It showed that combined poultry manure and plastic mulch could be an ideal combination for soil and water management and conservation for sustainable cucumber production in this area. © 2024 The Author(s)