Worm castings are the nutrient-rich waste produced by earthworms, particularly from species like the red wigglers. These castings are created as worms consume organic matter, such as decomposing leaves and food scraps, and then excrete it in a form that is beneficial for plants. Rich in essential nutrients like nitrogen, phosphorus, and potassium, worm castings improve soil structure and enhance its ability to retain moisture. They also contain beneficial microorganisms that promote healthy plant growth, making them a popular choice for gardeners and farmers looking to enrich their soil naturally.