Potassium, represented by the symbol K, is an essential nutrient for plant growth. It is involved in many physiological and biochemical processes, such as photosynthesis, enzyme activation, water and nutrient transport, protein and starch synthesis, and osmoregulation. Potassium also helps plants cope with stress, drought, disease, and cold. Plants take up potassium from the soil in the form of ions (K+), which are readily available in the soil solution or exchangeable with other cations on soil particles. However, not all soils can supply enough potassium for optimal plant growth, especially if they are sandy, weathered, or heavily cropped. In such cases, potassium fertilizers can be applied to supplement the soil's natural potassium reserves and prevent deficiency symptoms. Potassium deficiency can reduce plant growth, yield, and quality, as well as increase susceptibility to pests and diseases. Some common signs of potassium deficiency are yellowing or browning of leaf margins, curling of leaves, weak stems, and poor fruit development.