Pacific Northwest Lawn Care Calendar — Month-by-Month Guide

Lawn care timing matters in the Pacific Northwest because of our cool, wet winters and dry summers. Planning the right services at the right time maximizes results and strengthens turf health year-round.

Seasonal Service Windows

These serve as a general framework for professional lawn renovation services, including aeration, dethatching, overseeding, fertilization, and soil conditioning.

Spring (February–May)

• Prepare soil as it begins to warm and dry.

• Ideal period for core aeration, dethatching (power raking), overseeding, and starter fertilization.

• Early spring applications help increase turf density and support recovery after winter dormancy.

Summer (June–August)

• Manage grass stress during warm, dry weather.

• Use aeration where appropriate to improve moisture penetration.

• Avoid large seeding projects unless consistent irrigation is available.

Fall (September–November)

• Primary window for major renovation work.

• Best time for core aeration, dethatching (power raking), and overseeding.

• Cooler temperatures and increased rainfall support seed germination and root growth.

Winter (December–January)

• Focus on planning and lawn assessment, not heavy turf work.

• Observe drainage issues and prepare for spring service scheduling.

Optimizing Lawn Performance by Month

This schedule outlines when key lawn care tasks are most effective for cool-season turf common in Seattle and surrounding areas.

January–February

• Begin planning spring renovations and reserve service windows early.

• Minimize foot traffic on saturated turf.

• As soil conditions allow, prepare for aeration and seeding.

March–May

• Spring aeration, dethatching, and overseeding.

• Apply starter fertilizer after soil is receptive.

• Apply lime and soil amendments

• Adjust mowing height to promote recovery and strength.

June–August

• Implement moisture optimization strategies.

• If needed, apply summer treatments that enhance water penetration and limit stress.

• Avoid large seeding work unless consistent watering can be provided.

September–November

• Reserve this period for core renovation: aeration, dethatching, overseeding, fertilization and amendments.

• Cooler temperatures and fall precipitation enhance root establishment.

December

• Complete fall tasks early and start planning next year’s schedule.

• Use this time to schedule services rather than perform heavy lawn projects.

Service Windows at a Glance

Why Seasonal Timing Matters

Matching services to seasonal conditions helps:

• Improve seed germination and turf density

• Enhance soil structure and nutrient uptake

• Reduce stress during dry months

• Increase long-term lawn resilience