During winter seasons of 2017-2018 and 2018-2019, an experiment was conducted at a privet farm located in El-Sarou, Damietta governorate, Egypt, on onion growth, yield, and quality as affected by humic substances and foliar application with plant extracts. In split plot design, the experimental was consisted of 3 replicate having 15 treatments arrangement as; 5 treatments of humic substance (control, 2 and 4 kg for each humic and fulvic in form of potassium) as main plot, 3 levels of plant extract (without, 10 and 20 ml.L-1 mix from garlic and onion extract) as sub plot. The obtained results indicated that, soil addition of 4 kg.fed-1 potassium humate recorded highest significant values for growth traits, yield and its components as well as N, P, K, Fe, Mn and Zn in leaves and bulb, also, chemical and physical quality of bulb. On the same parameters, foliar application of 20 ml.L-1 from plant extract recorded the highest values. The combined application between 4 kg.fed-1 potassium humate with foliar 20 ml.L-1 plant extract was more prominent in enhancing the aforementioned parameters. Addition of potassium humate 4 kg.fed-1 increased available N, P, K mg.kg-1 and porosity, while decreased EC ds.m-1 in the soil after harvesting.