## 1 Introduction  
Nowadays, the main goal of modern horticultural production is to increase its quality. Recently, several innovative technologies have been suggested to improve the sustainability of agricultural production systems by significantly reducing synthetic agrochemicals such as pesticides and fertilizers. A promising and eco-friendly innovation is the use of natural plant biostimulants (PBs) that enhance flowering, plant growth, fruit set, crop productivity, and nutrient use efficiency and improve the tolerance against abiotic stressors [1]. Snap bean (_Phaseolus vulgaris_ L.) is among the most important leguminous crops that are of great interest in Egypt and in many developing countries, whether on the local consumer level or as a distinct export commodity [2]. The cultivated area of green beans in Egypt occupies 27,363 hectares, which is equivalent to 10,000 m\({}^{2}\), and the annual production of this area is 284,299 tons of green beans [3]. With the escalation of challenges in meeting the global requirements for food crops in terms of quantity, quality, and safety, there is a need to confront these challenges by searching for new effective, safe, and environmentally friendly agricultural systems, such as organic agriculture, which is currently successfully applied in some areas around the world [4; 5]. Biostimulants can be an interesting option in the face of degraded agricultural areas and uncertainties related to the changing climate. A biostimulant is defined as a complex product consisting of components of biological origin or microorganisms applied to plants either via root drench, foliar spray, or a combination of both, and is intended to improve plant productivity through new or emerging properties from its complex form and not as a sole result of the presence of known essential plant nutrients, plant growth regulators, or plant-protective compounds [6; 7]. Depending on their composition and expected results, biostimulants can be applied to soil or leaves [8]. Natural stimulants are often included under the term biostimulants, including humic acid, microorganisms (i.e., yeast), morning leaf extract (MLE), or vermicompost tea extract [9; 10; 11; 12; 13]. Although primarily associated with the enhancement of root growth [14], humic acid has also been shown to confer other benefits, such as increasing the mobilization of nutrients; improving photosynthetic rates, respiration, and water balance; and increasing the content of photosynthetic pigments [15]. [PERSON] et al. [16] found that the addition of humic acid at 20 g/L, novavol at 2.5 mL/L, or varimax at 0.2 mL/L significantly increased the height of snap bean plants, several leaves, branches/plant, leaf area, and the dry weights of shoots and roots among various biological changes. It is known that yeast is considered a natural source of cytokins that stimulate cell division and enlargement, as well as the synthesis of proteins, nucleic acids, and chlorophyll [17]. Foliar application of yeast extract increased amino acids, auxins, and cytokins 75 days after the sowing of broad bean [18]. Moringa leaf extract (MLE) is a potent plant biostimulant and can be used as a natural and alternative source of minerals, cytokins, antioxidants, amino acids, flavonoids, carotenoids, and vitamins [12]. The application of moringa leaf extract concentrations at 1:20, 1:30, and 1:40 positively affected the growth, biochemical properties, yield and yield-related traits, and pod quality of the snap bean compared to untreated plants [19]. How is vermicompost made? Vermicompost is formed through the process of converting organic materials into humus-like substances called vermicast, which is rich in organic matter and mineral nutrients, and the conversion process is carried out by earthworms and microorganisms [20; 21; 22]. It has been proven through many studies that vermicompost tea has many positive effects on the growth and productivity of crops, in addition to its ability to control plant diseases [13].