The application of wood ash in agriculture emerges as a promising technique to enhance agricultural productivity. Its chemical composition can improve soil attributes, acting as a fertilizer, corrective agent, and assisting in water retention. However, studies recommend controlled adoption to avoid adverse impacts. The objective of this article is to evaluate the potential of wood ash as a fertilization strategy in peanut cultivation, with an emphasis on optimizing plant productivity and reducing water deficit. The experiment was carried out in a greenhouse in 5 dm3 pots; the experimental design applied was randomized blocks, forming a 5x5 factorial scheme, corresponding to five doses of wood ash (0; 8; 16; 24 and 32 g dm-3) and five levels of water availability (25; 50; 75; 100 and 125% of field capacity), with four repetitions. The cultivar used was IAC OL-3. The data were subjected to the normality test to check whether they followed the normal distribution and, subsequently, subjected to analysis of variance and, when significant, subjected to regression analysis, at a 5% probability of error. Wood ash, rich in nutrients, proved to be a viable alternative source of nutrients. Doses between 18.4 and 22.8 g dm-3 of wood ash led to the most satisfactory results. The water availability that responded best ranged from 96 to 111.3%. Wood ash, at doses of 22.8 and 19.64 g dm-3, contributed to water consumption and soil water efficiency.