Why is my new lawn dying? Leatherjackets, clay and drainage
New-build lawns on the estate suffer from three common problems — here’s how to tell them apart.
Brown, patchy, dying grass — probably leatherjackets#
Leatherjackets (crane fly / daddy-long-legs larvae) eat grass roots and are widespread on the estate. Telltale signs: patches of grass that lift away easily with no roots, birds pecking at the lawn, and the grubs surfacing onto patios when it rains.
Treatment: nematodes (a natural, pet-safe biological control, widely available online):
- Autumn is the best time to apply — it catches the newly hatched larvae.
- Spring treatment also works — use it at double strength.
- Reseed straight after treating, and water daily while the new seed establishes. One resident’s lawn went from ruined to recovered in about a month doing exactly this.
Boggy garden — clay soil and compaction#
The estate sits on clay, and gardens were compacted during construction. Liquid gypsum (pet-safe) helps break up clay and improve drainage. Aerating with a fork before applying helps it penetrate.
Turf laid over rubble — that’s a snag, report it#
If your turf was laid over builder rubble, glass or nails, that’s a reportable defect, not something to live with — developers here have replaced turf and cleaned gardens after complaints. Report it to your developer’s customer care in writing.
And one general tip: don’t mow new turf for around 8 weeks after laying — let it root first.