Foliar Spray of Biostimulants as a Sustainable Strategy to Enhance Growth and Floral Productivity of Marigold (Tagetes erecta L.)

A field experiment was conducted during 2025 (April–August) at Department of Horticulture, College of Agricultural Technology, Kullapuram to study the effect of foliar application of biostimulants on growth, yield and quality of marigold (Tagetes erecta L.). The petals served as an excellent source of xanthophylls, with lutein accounting for 80–90 % of the total content, underscoring its significance beyond floriculture. The experiment consisted of five treatments viz., Fish Amino Acid at 3%, Panchagavya at 3%, Seaweed Extract at 3%, Vermiwash at 3%, and Control, laid out in a Randomized Block Design with four replications. Among the treatments, foliar application of Fish Amino Acid at 3% markedly enhanced growth parameters such as plant height (63.22 cm), number of branches (24.19) and number of leaves (251.15). It also recorded the highest physiological traits, including chlorophyll (49.34 SPAD) and leaf area (9.07 cm²). Yield attributed were similarly improved, with earliest flowering (34.73 days), maximum flower number (48.84), greatest individual flower weight (20.03 g), highest flower yield plant^-1 (978.27 g) and longest vase life (6.57 days). The findings confirmed that foliar application of biostimulants, particularly fish amino acid, was a highly effective method for improving the overall growth, yield, and quality of marigold.