Leatherjackets in Lawns: How to Identify, Treat and Prevent Damage in the UK
If your lawn has developed yellow patches, thinning grass, or turf that lifts easily like a loose carpet, leatherjackets could be the cause. These common UK lawn pests feed on grass roots beneath the surface, often going unnoticed until significant damage has already been done.
In this guide, we’ll explain what leatherjackets are, when they are most active in the UK, how to identify an infestation, and the most effective way to treat leatherjackets naturally.
What Are Leatherjackets?
Leatherjackets are the larvae of crane flies, often known as daddy-long-legs. Adult crane flies are commonly seen flying around gardens in late summer, particularly from August through September.
After mating, female crane flies lay eggs in lawns and grassy areas. Within around two weeks, the eggs hatch into grey-brown, cylindrical larvae known as leatherjackets. These larvae live in the soil and feed on grass roots throughout autumn, winter, and into spring.
Because they remain underground, many homeowners don’t realise they have a problem until visible lawn damage appears.
When Are Leatherjackets Most Active in the UK?
Leatherjacket activity typically follows this seasonal pattern:
- Late August – September: Adult crane flies emerge and lay eggs.
- September – October: Eggs hatch and young leatherjackets begin feeding.
- Autumn to Early Spring: Larvae continue feeding on grassroots.
- Spring: Damage often becomes more noticeable as grass struggles to grow.
The best time to treat leatherjackets in the UK is usually early autumn (September–October), when larvae are still small and more vulnerable to treatment.
Signs of Leatherjackets in Your Lawn
Leatherjackets damage lawns by feeding on grass roots, weakening the turf structure. Common signs include:
- Yellow or brown patches of grass
- Thinning turf or uneven growth
- Grass that pulls up easily
- Increased bird activity (starlings, crows, magpies)
- Badgers or foxes digging up areas of lawn
If birds are repeatedly pecking at your lawn, it’s often a sign that grubs or larvae are present below the surface.
Leatherjackets vs Chafer Grubs: What’s the Difference?
It’s important to correctly identify the pest before treatment.
Leatherjackets
- Grey or brown
- Cylindrical, worm-like shape
- No visible legs
- Tough outer skin
Chafer Grubs
- Creamy white
- C-shaped body
- Distinct orange/brown head
- Six visible legs
While both cause lawn damage, they require specific nematode treatments, so accurate identification matters.
How to Treat Leatherjackets Naturally
The most effective and environmentally friendly leatherjacket treatment in the UK is the use of beneficial nematodes.
Nematodes are microscopic worms that actively seek out leatherjackets in the soil. Once inside the larvae, they release natural bacteria that stop feeding and kill the pest. This method is known as biological lawn pest control.
Why Choose Nematodes for Leatherjackets?
- Chemical-free lawn treatment
- Safe for children and pets
- Safe for wildlife and pollinators
- Suitable for organic gardening
- Targets leatherjackets specifically
Because nematodes are living organisms, they work best in moist soil and suitable temperatures (typically above 10°C).
How to Apply Leatherjacket Nematodes
For best results:
- Apply in early autumn when larvae are small.
- Water the lawn before application if soil is dry.
- Mix nematodes with water as directed.
- Apply evenly using a watering can or sprayer.
- Water again after application.
- Keep the soil moist for at least two weeks.
Maintaining moisture allows nematodes to move through the soil and find the larvae.
Can Leatherjacket Damage Be Repaired?
Yes. Once the infestation is under control, lawns can recover with:
- Light raking to remove dead grass
- Overseeding bare patches
- Feeding with a suitable lawn fertiliser
- Regular watering during dry periods
Early treatment reduces long-term damage and repair costs.
Preventing Future Leatherjacket Problems
While it’s difficult to completely prevent crane flies laying eggs, you can reduce future risk by:
- Monitoring crane fly activity in late summer
- Applying nematodes at the correct time
- Maintaining a healthy, well-fed lawn
- Avoiding excessive thatch build-up
A strong, healthy lawn is more resilient to pest damage.
Final Thoughts
Leatherjackets are one of the most common causes of lawn damage in the UK, but they can be managed effectively with the right approach. Early identification and treatment with beneficial nematodes offers a safe, natural, and environmentally friendly solution.
If you suspect leatherjackets in your lawn, acting in early autumn gives you the best chance of protecting your turf and restoring a thick, green lawn for the seasons ahead.