improvement of growth characteristics, yield and postharvest quality of marigold (calendula officinalis cv. crysantha) by foliar application of humic acid

to study the effect of foliar application of humic acid on morpho-physiological traits, nutrients uptake and postharvest vase life of cut marigold, an experiment was conducted with five levels of humic acid (0, 250, 500, 750 and 1000 ppm) based on completely randomized design with three replications. based on the results, in compared with control, leaf number and leaf area, total phenol and aerial and root dry weight significantly influenced by humic acid. accordingly, the highest flower number in compare with control plants was observed in 250 and 500 ppm concentrations. also, foliar application of humic acid showed a significant effect on phosphorous and calcium uptake (p <0.05). in compared with control plants, flower vase life as the most important factor of postharvest quality, was 1.5 times higher in 250 ppm. results indicated a positive correlation between calcium absorption and flower vase life under humic acid foliar application. the results of the present study led to conclusion that, spray application of cut marigold flower (“crysantha”) with humic acid despite higher cut flower production, led to increasing of postharvest vase life.