The humic acid fraction of organic matter has a stimulating effect on the growth and development of ornamental plants. This study investigated the response in growth and yield of field-grown ornamental sunflower (Helianthus annuus L.) to the seed treatment with humic acids. The experiment was arranged in a randomized block design with three replications. Sunflower seeds were soaked in solutions of 0, 10, 20, 30, and 40mmol L-1 C in the form of humic acids and then sown in the flower beds. At harvest, the flower stems were collected to determine the variables: stem height, stem diameter, fresh stem weight, number of leaves per stem, leaf fresh weight per stem, leaf dry matter per stem, number of flower stalks, and diameter of the floral receptacle. Data... |