Unfavorable agro-ecological circumstances for grape agriculture have emerged in recent years as a result of climate changes, such as high air temperatures and a lack of precipitation. To counteract the negative repercussions, biostimulants are indicated for usage in plantations that have experienced stressful events such as drought, frost, nutrient deficiency, and plant disease. Furthermore, the usage of silicon-based preparations alleviates stress caused by insects, infections, and climate change. An experiment was conducted on Žilavka vines at a family farm in Kočina, near Mostar, during the 2025 crop year. Seven treatments were used to assess the impact of various preparations. To assess the influence of different kinds on mechanical composition, the weight of bunches, petioles, and berries were examined, as well as the sugar and acid content of grapes. Plasmopara viticola was also present this year, along with Lobesia botrana; both species caused serious damages. Every day, the vineyard's air temperature and precipitation were measured. Statistical data analysis using the ANOVA test revealed substantial differences between the variants, whereas the LSD test allowed for accurate comparisons of individual variants. The results demonstrate that Variant 5 significantly increased the weight of the bunches compared to the other treatments, although Variants 2 and 4 had a higher sugar content, indicating a varied effect of the preparation on the examined grape characteristics.