Two field experiments were conducted to evaluate the effect of different levels of organic fertilizer (5, 10 and 15 m³ compost/fed.) when used with half dose of chemical fertilizer compare with full dose of chemical fertilizer in presence of ascorbic acid foliar spraying (0.0, 100 and 200ppm) on some growth parameters, yield and chemical constituents of roselle (Hibiscus sabdariffa L.) plants during 2011 and 2012 seasons. Interaction effects between ascorbic acid and the used fertilization treatments on growth and productivity were studied as well. The results showed that either treatment of half chemical fertilizer dose+15m³ compost/fed. or full chemical fertilizer dose significantly induced the highest values of plant height, number of leaves, branches and fruits /plant, leaves dry weight/plant, fresh and dry weight of branches and sepals/plant, seed yield/plant, seed fixed oil per plant and per fed., sepals anthocyanin and vitamin-C content, leaf N, P, K, Fe, Zn and Mn uptake, leaf total carbohydrates, total sugars, total free amino acids, auxins, gibberellins and cytokinins content, but they decreased the values of leaf abscisic acid, peroxidase, catalase and superoxide dismutase contents. However, the highest number of leaves, branches and fruits/plant, the heaviest leaves dry weight/plant, the heaviest fresh and dry weights of sepals/plant, the highest seed fixed oil content per plant and per fed., the highest sepals vitamin-C contents, the highest leaf N, K, Fe and Mn uptake, the highest values of chlorophyll a&b, carotenoids, total carbohydrates, total sugars, total free amino acids, gibberellins and cytokinins as well as the lowest values of abscisic acid, peroxidase and superoxide dismutase were recorded by half chemical fertilizer dose+15m³ compost/fed. treatment combined with 200ppm ascorbic acid. Besides, the highest sepals anthocyanin content was recorded by the combined treatment between half chemical fertilizer dose+10m³ compost/fed. and 200ppm ascorbic acid in both seasons. Moreover, the tallest plants, the heaviest fresh and dry weight of branches/plant, the highest seed yield/plant, the highest leaf P and Zn uptake and the highest leaf auxins content of roselle plants were scored by the full chemical fertilizer dose combined with 200ppm ascorbic acid, followed by the combined treatment between half chemical fertilizer dose+15m³ compost/fed. and 200ppm ascorbic acid in both seasons. Consequently, it could be safely treat roselle plants with the combined treatment between half dose of chemical fertilizer+15m³ compost/fed. and ascorbic acid at 200 ppm for enhancing growth and productivity of this plant.