To study the effect of humic acid on yield and yield components of marigold, a complete randomized experiment with 5 levels of humic acid treatments (0, 500, 1000, 2000, 4000 mgl-1) with 3 replications and 15 experimental plots was carried out. Analysis of variance showed that the effect of humic acid treatments on number of leaves and flowers, dry weight and plant height was significantly at the 1% probability level. Mean comparisons revealed that treatment with 2000 mgl-1 humic acid, had the most dry weight, plant height, leaves and flowers number.
