Abstract The present investigation was undertaken throughout the two successive seasons of 2016 and 2017 at fruit orchard, Faculty of Agriculture at Moshtohor, Benha University, Toukh region, Qalyubeia Governorate, Egypt. The main goal from study evaluate the effect of some stimulating substances i.e., (yeast extract and nano fertilizer) at different concentrations and irrigation levels on some vegetative growth measurements and leaf nutritional status of Washington navel orange trees budded on sour orange rootstock. Results indicated that, all investigated stimulating substances treatments under study as foliar spray at various concentrations and irrigation with high level resulted in a positive and significant increase in most vegetative growth measurements and improving leaf nutrient contents of Washington navel orange trees in comparison with the control during both seasons of study. The best results were obtained from sprayed trees with yeast extract at 150 ml/liter+lithovit at4.0g/liter  and irrigation with 3894.1 m³ water / feddan / year compared to the water spray and irrigation with 3127.8 m³ water /feddan/year during both seasons of study.