Increasing drought caused by climate change poses a significant challenge to potato production. In our experiment conducted in Sonkád (Hungary), different leaf treatments and irrigation regimens were tested over two growing seasons in a randomized block design using the Manitou variety. During the experiment, three irrigation rates (full, 50%, and dry control) were used, along with four foliar treatments – salicylic acid, hydrogen peroxide, silicon, and micronutrients – which were applied exclusively to the non-irrigated plots. A total of seven different treatments were carried out in four replicates. Based on the results from the two growing seasons, the silicon, hydrogen peroxide, microcomplex, and salicylic acid foliar treatments significantly increased the relative chlorophyll content (SPAD) compared to the control and the irrigated treatments. On average over the two years, the NDVI value was significantly increased by the silicon, hydrogen peroxide, microcomplex, and salicylic acid foliar treatments compared to the control, and no statistical difference was observed in performance between the full-dose irrigation treatment and the listed treatments. NDVI measurements taken at various time points confirmed that treatments with the tested substances were able to slow chlorophyll degradation and maintain the integrity of the photosynthetic apparatus even during the critical post-flowering period. In the case of the leaf area index, the highest value was observed in the treatment irrigated with the full dose, but no significant difference was found compared to the performance of the silicon, hydrogen peroxide, microcomplex, and salicylic acid treatments. At the same time, the most important indicator in terms of yield was irrigation, which had a significant impact in both years. Although the foliar treatments mitigated stress and improved plant vitality, they did not result in a statistically significant increase in yield compared to the untreated control.