This experiment was carried out at the Agricultural Research Station of the Agricultural Research Center in Gemmayzeh, Gharbia Governorate, Egypt during the two consecutive summer seasons of 2019 and 2020, with the aim to evaluate the effect of vernalization and some organic acids (citric and ascorbic acids) on roselle (Hibiscus sabdariffa L.) plants. The combined treatments were as follows, NPK 100% only (cont.) + vernalization (T1), cont. + non-vernalization (T2), ascorbic acid in addition to NPK 50% (AA) + vernalization (T3), AA + non-vernalization (T4), citric acid in addition to NPK 50% (CA) + vernalization (T5), CA + non-vernalization (T6), AA + CA + vernalization (T7), AA + CA + non-vernalization (T8). It was found that the effect of vernalization and some organic acids on plants gave highly significant values compared to control on all tested vegetative growth traits and chemical measurements. The best spraying treatments were recorded by citric acid on most vegetative measurements i.e. plant height (cm), weight of 100 seeds (g), fixed oil % etc. The vernalization recorded the best results on all parameters under study. Regarding the combined treatments between these two factors, the highest values of the studied characteristics (vegetative growth traits, fixed oil % and the organic acid i.e. stearic and linoleic acids) were obtained by T7 and T5. In general, applying T7 (ascorbic + citric acids (in addition to NPK 50%) + vernalization) is recommended to obtain the best results for the most studied measurements of roselle.