The present investigation was performed in Horticultural Research Station, Mondouri, Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal during 2017 to 2018 to assess the best dose of humic acid and vermicompost combination for African marigold. The experiment was designed in Randomised Block Design (RBD) with three replications. There were four concentrations of humic acid extracts (0.5 g/l, 1.0 g/l, 1.5 g/l and 2 g/l) applied as a foliar spray in combination with basal doses of vermicompost (1 kg/m2 and 2 kg/m2). All the parameters showed significant differences regarding vegetative, flowering as well as quality parameters. The results indicated that foliar spray with 1.5 g/l of humic acid extract along with 2 kg/m2 vermicompost significantly increased plant height (54.54 cm), number of primary branches (7.21), flower diameter (7.44 cm), fresh weight & dry weight of flower (9.06 g & 1.2 g respectively), number of flowers per plant (84.16), yield per hectare (47.01 tons/ha) as well as the quality parameters. So, among the nine treatments, T8 (Humic acid 1.5 g/l + 2 kg vermicompost/m2) was the best combination for improving plant growth, yield and quality of African marigold in the Indo-Gangetic plains of West Bengal.