One of the most important elements that enhances plant growth, productivity, and development is the integrated the supply of nutrients and growth stimulants in the proper amounts and ratios. Two field experiments were carried out during seasons of 2021/2022 and 2022/2023 at Eastern Experimental Field, Vegetable Crops Department, Faculty of Agriculture, Cairo University, Giza, Egypt to investigate the effects of foliar spray of 6 growth stimulants treatments, humic acid, amino acids, algae extract, micro-elements mixture, moringa extract and ascorbic acid, on growth, productivity, 
chemical composition and storability of onion plants (Giza 20). This experiment was done in a randomized complete block design with 3 replicates. The results indicated that foliar spray of all growth stimulants exhausted a significant improvement of onion plant height, number of leaves, bulb diameter, neck diameter, total yield, TSS% after one month of storage, activity of antioxidant enzymes, ascorbic acid and total phenolic in both seasons, as compared with control 
and spraying with humic acid and ascorbic acid gave the highest total yield / feddan. The highest values of average bulb weight were found with foliar spray of humic acid and amino acid in both seasons. Using humic acid in both seasons or amino acids and micro elements treatments in the first season significantly decreased weight loss%, compared to control.