The application of biofertilizers constitutes one of the main components of nutrient management with a fundamental role in sustainable agriculture and the improvement of plant qualitative traits. The present research assessed the effect of various treatments of phosphate solubilizing bacteria including Pantoea agglomeransstrain P5 and Pseudomonas putida strain P13 (seed inoculation, the application of biofertilizer 2, 4 and 6 weeks after plant emergence, and no inoculation of seeds as control treatment) and the foliar application of ZnSO4 (at 0, 1, 2, and 3 gL-1 rates) on morphological and biochemical traits of marigolds. It was found that the highest plant height and flower fresh weight belonged to plants whose seeds were inoculated with biofertilizer and were fertilized with 2 g L-1 ZnSO4 and also, in plants treated with biofertilizer 2 weeks after plant emergence and fertilized with 1 and 2 g L-1 ZnSO4. Also, the highest flower dry weight and anthocyanin content were obtained from the treatments of biofertilizer 2 and 4 weeks after plant emergence supplemented with 1 and 2 gL-1 ZnSO4. The highest P content was seen in the treatments of biofertilizer 4 and 6 weeks after plant emergence × 2 and 1 gL-1 ZnSO4. In addition, the highest Zn content was obtained from biofertilizer application 6 weeks after plant emergence and in plants fertilized with 3 gL-1 ZnSO4. In contrast, the lowest amount of most parameters was observed at different levels of biofertilizer application without the use of ZnSO4 and with the use of 3 gL-1 ZnSO4. Therefore, the foliar application of ZnSO4 and the soil application of phosphate solubilizing fertilizers can influence the biochemical and morphological traits of marigolds. Manuscript profile