A field experiment was carried out to determine the best rate of potassium humate and optimum concentration of GA₃ in a sandy soil to optimize the growth, biomass, and chemical composition of gladiolus plant (Gladiolus hybrida cv. Sancerre). Four different rates of K-humate 0.00, 2.0, 4.0 and 6.0 g plant^-1  was added K- humate was applied at 15 days intervals (first one after 15 days from planting) with four levels of gibberellic acid (GA₃)at 0.00, 50, 100 and 150 ppm as foliar spray. Treatments were implemented in a split-plot design with three replications, in both seasons.
The main results of this study can be summarized in the following points:
I- The results showed that using the different rate of K-humate had a significant effect on all the vegetative growth characteristics. Potassium humate at 5g gave the highest reduction for the time required to flowering stage (day), the maximum of florets number, and inflorescence weight (g). The highest significant increase in the chlorophylls in fresh leaves and potassium content (%) in the leaves were obtained by using 3 and /or 5g plant ^-1.
II- Plant height, leaf length, leaves area and dry weight of leaves/plant (g) significantly increased with increasing levels of GA₃, with not significant differences among concentration 100 and high level at 150 ppm compared with control treatment in most cases. The highest values of plant height, leaf length, leaves area and leaf weight were obtained by adding 150 ppm. All levels of gibberellic acid were significantly advanced the time flowering, and the highest concentration produced the maximum increase in flower quality and quantity. Chemical analysis showed with increasing GA₃ led to a significant increase in the chlorophylls content and K percentage in the leaves.
III- Using K-humate with gibberellic acid at 150 ppm gave the maximum beneficial effect on growth characters. The best characters of flowers production were recorded by adding the high level of potassium humate 6g /plant combined with 100 and/or150 ppm GA₃, it produced the highest reduction for the time required to flowering stage and the highest number of florets, and heaviest dry weight of inflorescence for both seasons.  Chlorophylls and K content of leaves showed that there was significant effect for K-humate with gibberellic acid on the chemical composition.
IV- The results of chemical analysis showed an improvement in the leaf content of chlorophyll (31.98 to 58.76 SPAD), potassium percentage (2.13 to 3.98%).  and total carbohydrates  (14.86 to 23.37 % ) as well as the content of new corms ( total carbohydrates  36.91 to 47.54 %), as a result of treatment with both K- humate and gibberellic acid compared to the control treatment plants.The best value was recorded by using 6 g/plant of K-humate with 150 ppm GA₃.