Two field experiments were carried out at a private farm, El-Taweila Village, near El-Mansoura City, Dakahlia Governorate, Egypt during the two summer seasons of 2019/2020 and 2020/2021. The study aims to investigate the role of seaweed extract at 0.5 g/L, bacterial mixture of Bacillus paramycoides and Azotobacter nigricans at 1 cm³/L and potassium phosphite at 2.5 cm³/L individual or in combination as foliar applications on vegetative growth, tuber yield and tuber quality of potato cv. Kara. The obtained results showed that all studied treatments increased vegetative growth (plant height, leaves number per plant, stolons number per plant and fresh and dry weight per plant) and tuber yield (tuber weight, tuber dry matter, tubers number per plant and tuber yield per fed) as well as improved tuber quality (N, P, K, starch and carbohydrates percentages) compared to control. The results suggested spraying potato plants with seaweed at 0.5 g/L, the bacterial mixture of Bacillus paramycoides and Azotobacter nigricans at 1 cm³/L and potassium phosphite at 2.5 cm³/L to improve the vegetative growth and increase the tuber yield and quality under similar conditions of the study.