What are worm casts and how do you manage them?
Worm casts are those small, muddy, sludgy clumps that often appear on the surface of lawns, particularly in autumn. These casts are the waste products left behind by earthworms, a sign of a soil that’s thriving and healthy. While these small mounds may seem like a nuisance to some, they play a crucial role in maintaining a balanced garden ecosystem.
Why worm casts are a good sign
Earthworms are essential contributors to the garden ecosystem, enriching the soil and supporting plant health. Their activity helps aerate the soil, ensuring it’s well-structured and oxygenated. As earthworms feed on dead plant material, they consume and process a certain amount of soil, releasing nutrients into the soil with their castings. In fact, the presence of worms indicates a nutrient-rich, structured soil that helps ornamental gardens and vegetable plants grow vigorously.
Worms are a vital part of the food chain, serving as a source of nourishment for birds, hedgehogs, and amphibians. So, while their castings may create a bit of surface mess, they are ultimately a positive indicator of a healthy ecosystem.
The Impact of Worm Casts on Lawns and Gardens
Worm casts generally don’t cause issues and can be tolerated in most garden settings. However, for finely manicured lawns and pathways, worm casts can become an aesthetic and practical problem. On formal lawns, such as those at corporate venues or turf farms, worm casts may look unsightly as they turn the grass muddy. They can also disrupt the smooth, level surface required on sports turf, like golf courses and bowling greens, where they can affect the quality of play.
When worm casts are flattened by a lawnmower, they create small bumps that not only disrupt the turf’s appearance but also provide prime spots for weed seeds to settle and germinate. For these reasons, casts in formal gardens or sports turf may require careful management.
Tips for Managing Worm Casts in Lawns
If worm casts are affecting the appearance or usability of your turf, here are a few simple strategies for managing them effectively:
1. Let casts dry, then brush them off – Allow the castings to dry completely, then gently brush them back into the turf. This is especially helpful to do just before mowing to prevent them from spreading and causing further mess.
2. Follow a year-round lawn maintenance program – Regular lawn care practices, including consistent mowing, fertilisation, and aeration, can help reduce the number of worm casts on your lawn. Regular rolling can also help to discourage surface disruption.
3. Collect grass clippings – After mowing, collect grass clippings, which can minimise the organic material left behind and may slightly reduce worm activity on the surface.
4. Avoid washing casts away with water – It might be tempting to hose the castings off, but this can backfire. Excessive water can drive more worms to the surface as they seek to escape overly wet soil.
On paths or hard surfaces, you can simply use a trowel to remove dry casts. It’s worth noting that worm activity peaks in autumn and early spring, with mild winters potentially allowing for continued activity throughout winter. During these seasons, it’s best to avoid walking on the lawn when possible to prevent flattening the casts into the grass.
The Benefits of Natural Turf with Earthworms
Naturally produced turf, especially when sourced from a responsible supplier such as a TGA member, often contains earthworms. While you might notice casts on newly laid turf, their presence indicates that the turf was grown with environmental standards in mind, free from chemical worm controls. Turf produced with these methods supports a healthy lawn ecosystem from the start, bringing you a greener and more resilient lawn.
Worm casts may not be ideal for every lawn type, particularly finely manicured or high-traffic lawns. However, by taking a few simple steps to manage them, you can enjoy the benefits of a healthy, worm-friendly lawn and contribute to the overall vitality of your garden’s ecosystem. Embrace these signs of healthy soil after all, a little patience with worm casts can go a long way in supporting a thriving, balanced garden.
