This research study was carried out in the open field during the two successive seasons of 2012/2013 and 2013/2014. The aim of this investigation was to study the response of pot marigold (Calendula officinalis L.) to different application methods and concentrations of seaweed extracts applied as a commercial compound. Seven treatments were initiated, i.e. three concentrations of seaweed extracts (500, 1000, 1500) were used either as foliar spray or as soil drench in addition to the control treatment (tap water). Results indicated that foliar spray with 1500 ppm of seaweed extract increased significantly plant height, number of flowers per plant and vase life in the two tested seasons. However, foliar spray with the lowest concentration of seaweed extract (500 ppm) resulted in significant increments in flower stalk length, flower diameter and carbohydrates content. Moreover, the same concentration showed significant increases in total carotenoids, nitrogen, and phosphorus percentage when used as soil drench in the two tested seasons.