Enhancing Sweet Cherry Quality Through Calcium and Ascophyllum nodosum Foliar Applications

Climate change significantly impacts fruit production and yield, affecting its commercial value. Foliar fertilization emerges as a fast and targeted strategy to address crop nutrient deficiencies and enhance fruit quality. Sweet cherry is among the most highly valued and widely appreciated fruit crops globally. This study was conducted over two consecutive years on the sweet cherry cv. Sweetheart. Calcium (300 g hL−1 and 150 g hL−1) and a seaweed-based biostimulant (150 mL hL−1 and 75 mL hL−1), as well as a combination of both nutrients (300 g hL−1 calcium and 150 mL hL−1 seaweed), in addition to a control treatment (water), were applied at the foliar level to improve sweet cherry quality. To assess cherry quality, including biometric, chromatic, texture, and biochemical parameters, as well as the sensory analysis, fruits from each treatment were harvested at the commercial maturity stage. Calcium treatments improved fruit size, total soluble solids, and firmness, while also delaying fruit ripening by increasing titratable acidity. The seaweed-based biostimulant enhanced fruit size, promoted color development, and accelerated ripening. Together, these findings highlight the crucial role of calcium in improving sweet cherry quality and underscore seaweed-based biostimulants as a promising and sustainable strategy for enhancing fruit quality. Although cherry quality is highly affected by environmental conditions, this study demonstrated that calcium fertilization, either alone or in combination with seaweed, enhances sweet cherry quality attributes, making it a suitable strategy for application in commercial orchards and for the global improvement of sweet cherry production.