Watering New Grass Seed in Cool Weather: When to Stop

You seeded 16 days ago in the northern Chicago suburbs. Some areas show germination; others don’t. With temperatures dropping into the 30s and 40s °F, should you keep watering?

Guidelines for Late-Fall Seeding

• If daytime highs are consistently below 50 °F, germination will pause. Seed will remain viable and resume growth in spring.
• Stop daily light watering once temps stay in the 30s–40s. It’s unnecessary and can encourage fungal issues.
• If you continue, water deeply (1 inch) infrequently to saturate the root zone, then allow the surface to dry before rewetting.

Uneven Germination?

Sunny areas may dry out faster—evaporation can steal light irrigation before it reaches the seed. Deep, infrequent watering solves this. Also, seed quality varies; some modern batches germinate less uniformly.

Come spring, overseed any thin spots. Seed is cheap; patience pays.