The article presents the results of a study on the effect of treating safflower and flax seeds with plasma-activated water solutions containing various concentrations of hydrogen peroxide. The research focuses on the impact of this technology on seed germination and crop yield under high-temperature conditions. It was found that treating seeds with a 0.75% solution of biologically active water, activated by hydrogen peroxide plasma, led to an increase in yield. Specifically, safflower showed a yield increase of 1.8–2.5%, while flax demonstrated an increase of 1.0–2.8% compared to the control group. In absolute terms, this corresponds to 0.7–0.8 quintals per hectare for safflower and 0.2–1.0 quintals per hectare for flax. The obtained data indicate the potential of using plasma-activated water to enhance the productivity of oilseed crops under stressful temperature conditions.