When trying to assess the worm activity in your garden, one of the most obvious things to look out for is the presence of castings. These may sometimes appear as mounds in the lawn, or you can check the surrounding soil by making a small hole and looking for the castings. During this assessment, you’ll probably also see the worms themselves. Another great way to understand whether there are worms is by looking at the health of your plants. Healthy plants are an indicator that the soil is good, and this is likely a result of the work of worms.