When you think about creating a lush, healthy lawn, your first thoughts probably turn to quality lawn seed, regular mowing and perhaps a good fertiliser. But what’s happening beneath the surface of your garden is just as important – and that’s where worms come in.
Not all worms are equal. Some are nature’s hidden heroes, quietly transforming your lawn from the ground up. Others, although less common in the UK, can cause headaches for gardeners. So, let’s dig in – pun fully intended – to the good worms and bad worms you might encounter in your lawn or compost heap.
The Good Guys: Earthworms & Compost Worms
Earthworms (Lumbricus spp.)
These native worms are a gardener’s best friend—especially if you’re looking to maintain a healthy, green lawn. Here’s how they help:
- Improve drainage: Their tunnels allow rainwater to flow through your soil rather than pooling on your lawn
- Boost aeration: Oxygen reaches grassroots more easily, promoting stronger, more resilient turf
- Enhance soil fertility: Earthworms consume organic matter and excrete castings rich in nitrogen, phosphorus and potassium – the key ingredients your lawn loves!
A good earthworm population is often a sign of excellent soil health. If your soil is compacted, however, these helpful wrigglers might struggle to move through it – so aeration and overseeding with high-quality grass seed can help bring them back.
Compost Worms (Eisenia fetida / Red Wigglers)
You might not find these directly in your lawn, but if you’re into composting, you’ll definitely want them on your team. These worms thrive in kitchen waste and decomposing material, turning scraps into nutrient-rich compost that can be used to top-dress your lawn in spring and autumn.
Top tip: Composting your lawn clippings and using a wormery to manage food waste is a brilliant way to recycle nutrients back into your garden sustainably.
The Bad Guys: Should You Be Worried?
Invasive Jumping Worms (Amynthas spp.)
While not widespread in the UK (yet), these worms are a concern in North America and Asia and conservationists are keeping a watchful eye. They break down organic matter too aggressively, leaving soil crumbly and depleted – bad news for plants and grass roots alike.
If you spot an unusually active, snake-like worm that jumps when disturbed (up to 30cm in the air!), it’s worth reporting it to DEFRA. Better safe than sorry.
New Zealand Flatworm (Arthurdendyus triangulatus)
Another unwelcome guest in UK gardens is the New Zealand flatworm, a predator of our native earthworms. These flatworms are dark brown with a pale edge and can grow up to 15cm long. Unlike earthworms, they don’t help your lawn – in fact, they can do serious harm by devouring the very worms your soil depends on. As earthworm numbers decline, so too does soil structure, drainage and fertility – all of which are vital for a healthy lawn.
Flatworms tend to hide under pots, stones and black plastic sheeting, especially in cool, damp conditions. If you find them, avoid spreading soil or compost from the affected area and report sightings to help monitor their spread.
How to Encourage Good Worms in Your Lawn
If you want worms to work with you, here’s how to make your lawn a worm paradise:
- Top-dress with compost: Use homemade compost or composted manure to feed the soil and attract earthworms
- Avoid pesticides: Many chemical treatments harm worms and the microbes they feed on
- Aerate your lawn: Compacted soil is tough on worms. Regular aeration helps them – and your grass – breathe
- Mulch with clippings: Leave grass clippings on the lawn occasionally to break down and feed the soil ecosystem
Composting: Your Lawn’s Secret Weapon
Integrating a composting system in your garden is one of the most powerful, eco-friendly ways to support your lawn. It reduces waste, improves soil structure and encourages a thriving worm population. Whether you’re using a traditional compost bin or a wormery filled with red wigglers, the result is the same: nutrient-rich material that your lawn will love.
Final Thoughts
Your lawn’s health starts underground. By understanding the difference between good and bad worms, you’re not just maintaining your garden – you’re actively improving the environment it depends on.
Ready to support your lawn from the soil up? Pairing the right lawn seed with worm-friendly practices could be the secret to the greenest grass on the block.