Fertilizer is a substance added to soil or plants to provide essential nutrients that promote growth. It typically contains key elements like nitrogen, phosphorus, and potassium, which are vital for plant health. Fertilizers can be organic, derived from natural sources like compost or manure, or synthetic, made through chemical processes. Farmers and gardeners use fertilizers to enhance crop yields and improve the quality of fruits and vegetables. Proper application of fertilizers can lead to healthier plants and more abundant harvests, but overuse can harm the environment by causing soil and water pollution.