Earthworm Castings: What They Mean and What to Do

How to Manage Earthworm Castings

You cannot and should not try to get rid of earthworms, but you can reduce how noticeable the castings are with a few simple steps.

• Rake dry castings across the lawn When the castings have dried out, simply rake or brush them across the surface. They will settle down into the grass roots and act much like an organic fertiliser, putting nutrients back into the soil.
• Remove wet castings by hand If wet weather means the castings are not drying out, you can pick or rake them up while they are still damp and add them to your compost bin. They are rich in digested organic matter and will be a welcome addition.
• Give the area a quick rinse A brief blast with the hose can wash castings down into the lawn and reduce their appearance. Keep it short though, because extra water encourages more worm activity near the surface, so only do this when castings are particularly heavy.
• Raise your mowing height Mowing on a slightly higher setting means castings are less visible among the longer leaf. It is a quick way to take the edge off the appearance while conditions are wet.
• Reduce surface food sources Earthworms come up to feed on clippings and leaf litter. Rake up fallen leaves regularly and mow with a catcher attached to remove clippings. With less food available at the surface, worms will head back below ground.
• Top dress with a sandy mix Applying a top dressing with a high sand content helps lower moisture levels near the surface, encouraging worms to move deeper into the soil. Do this during the warmer months when your lawn is actively growing and can recover quickly.
• Ease back on watering Because worm activity increases with moisture, cutting back irrigation during wet spells will encourage worms to go deeper in search of water. During prolonged rain there is little you can do, but adjusting your watering schedule during drier stretches will help.