Biostimulants are natural substances or microorganisms that enhance plant growth and health by improving nutrient uptake, promoting root development, and increasing resistance to environmental stress. They work by stimulating biological processes in plants, leading to improved growth, yield, and overall resilience. Biostimulants can include humic acids, seaweed extracts, amino acids, and beneficial bacteria or fungi, making them a valuable tool for sustainable agriculture and horticulture.