London, ON Lawn Care Guide
London sits in the Great Lakes & Ontario climate zone. Browse seasonal guides below to keep your lawn looking its best year-round.
Seasonal Guides
Compatible Grasses for London
Lawn Growing Conditions in London
London sits in Canada Plant Hardiness Zone 6a, with summer highs of 25°C to 32°C and winter lows reaching -15°C to -25°C. The frost-free growing season runs approximately Mid-May to mid-October — April to October (6 months). Annual precipitation of 700–850mm means supplemental irrigation is important during summer dry periods.
Key Dates for London Lawn Owners
Common Lawn Problems in London
White grubs
When: August–September
European Chafer and Japanese Beetle larvae feed on roots. Signs: irregular brown patches, turf lifts like carpet, skunks and raccoons digging at night. Apply beneficial nematodes in August when soil is moist and warm.
Brown patch
When: July–August (hot, humid)
Circular brown patches 15–60cm across in Kentucky Bluegrass during humid weather above 27°C. Improve airflow, avoid evening watering, and reduce nitrogen. Fungicide only for severe cases.
Crabgrass
When: May–June germination
Annual weed that germinates when soil reaches 12°C. Pre-emergent herbicide in May (when forsythia blooms) is the only effective prevention. Once visible, crabgrass cannot be stopped — only pulled by hand.
Frequently Asked Questions
What is the best grass for London, ON?
London, ON sits in the Great Lakes & Ontario climate zone, so the best-suited grasses are Kentucky Bluegrass, Fine Fescue, Perennial Ryegrass. Kentucky Bluegrass is the most popular choice for its cold hardiness and self-repairing rhizomes. Fine Fescue is excellent for shaded areas.
When should I fertilise my lawn in London, ON?
For cool-season grasses in London, ON, apply the first fertiliser in spring once soil temperature reaches 10°C. The most important applications are in fall — a September feed for root development and an October winteriser with high potassium to harden the lawn for winter.
How often should I water my lawn in London, ON?
In London's Great Lakes & Ontario climate, water deeply once or twice per week during summer, applying around 25mm per session before 9am. Cool-season grasses can go dormant in drought and recover — overwatering is often worse than underwatering. Adjust based on rainfall.
Why is my lawn in London, ON turning brown?
Brown patches in London, ON lawns are commonly caused by: summer drought dormancy (normal for Kentucky Bluegrass), grub damage (European Chafer or Japanese Beetle larvae), fungal disease (brown patch or dollar spot), or snow mould in spring. Check soil moisture first — if the ground is dry, dormancy is likely the cause.
When is the best time to overseed in London, ON?
The best time to overseed in London, ON is late August to mid-September when soil is warm and air is cool. Aerate first, then overseed at 35–50g per m² and water daily for 2–3 weeks. Spring overseeding (May–June) is possible but less successful due to summer heat stress on new seedlings.