Two field experiments were carring out  during the two successive early summer seasons of 2017 and 2018 at the farm of the Department of Horticulture, Faculty of Agriculture in Mashtoor, Benha University, Qalyubia Governorate to study the effect of soil addition of effective  microorganisms (EM) and foliar spraying with salicylic acid, urea phosphate and seaweed extract individual  or in combinations  on Vegetative growth characteristics, photosynthesis characteristics (chlorophyll a, b, and carotenoids), chemical composition, total yield, and quality characteristics of sweet pepper (Capsicum Annuum,L. California Wonder.) The experiment included 14 treatments, which are as follows: the effect of beneficial microorganisms (EM) at a concentration of 100 ml / liter seaweed extract at a concentration of 1 and 2 grams / liter, salicylic acid at a concentration of 100 and 200 ppm / liter, urea phosphate at a concentration of 2 and 4 Gram / liter, in addition to the control treatment (without spraying). The obtained results indicated that the highest values ​​in vegetative growth characteristics, photosynthesis characteristics (chlorophyll a, b and carotenoids), chemical composition, total yield, and quality characteristics of sweet pepper fruits were obtained as a result of adding microorganisms. The beneficial (EM) at a concentration of 100 ml / liter as a soil addition with spraying pepper plants with urea phosphate at a concentration of 4 g / liter three times during the growing season, starting after 20 days of seedlings and once every 20 days in order to improve vegetative growth and increase productivity under conditions of low temperatures in the open field.