Bio stimulant-Driven Improvement of Growth, Yield, and Phytochemical Traits in White and Red Cabbage

White and red cabbages (Brassica oleracea var. capitata) are economically and nutritionally significant cruciferous vegetables. Optimizing agronomic practices to enhance their growth, yield, and biochemical quality is essential for sustainable production. To this end, a field experiment was conducted during the 2024 growing season to evaluate the comparative response of white and red cabbage varieties to foliar applications of two bio-stimulators: Viviter Veg and Pow Humus. The study utilized a Randomized Complete Block Design (RCBD) with a factorial arrangement and three replications. Treatments included three concentrations of Viviter Veg (0, 10, and 20 ml/L) and Pow Humus (0, 4, and 8 g/L), applied three times at 15-day intervals commencing three weeks after transplanting. Parameters assessed included plant height, head fresh and dry weight, total yield, chlorophyll content (SPAD), as well as carbohydrate and phenolic content. Analysis of variance revealed that bio-stimulator application significantly improved all vegetative and biochemical traits compared to the control. Notably, the white cabbage variety demonstrated significantly superior performance over the red variety across most parameters, recording a higher total yield of (37.50 t/ha) compared to (24.12 t/ha) for red cabbage. Furthermore, Pow Humus exhibited a greater impact on yield characteristics than Viviter Veg. The highest values for most parameters were recorded with the application of Pow Humus at 8 g/L, which achieved a head fresh weight of (750.24 g) and a total yield of (37.50 t/ha), followed by Viviter Veg at 20 ml/L. These findings suggest that the foliar application of Pow Humus at 8 g/L is an effective strategy for maximizing the productivity and nutritional quality of cabbage, particularly for the white variety.