Answer: Earthworms often come to the soil surface when the soil is saturated with water. Since they glide on the water, they can be suddenly become stranded in the sunshine if that source of water quickly dries up. That's why you may see dead earthworms on sidewalks after a summer rain. Earthworms are also quite sensitive to chemicals commonly used on lawns and in garden beds, especially dursban and diazinon. If you've used those chemicals against cutworms and grubs, you've also reduced the earthworm population. Now that you know the potential causes, perhaps you can narrow down the cause of dead earthworms in your yard.
Q&A Library Searching Tips