A simple fertilizer schedule for Illinois lawns
Lawn fertilizer marketing wants you on a five-step program. Most Chicagoland lawns thrive on three well-timed feedings — and the most important one is the one people skip.
The three-feeding plan
| When | What it does |
|---|---|
| Late spring (May) | Light feeding after the spring flush — supports the lawn without pushing crazy top growth |
| Early September | Recovery from summer; fuels fall thickening (pairs perfectly with overseeding) |
| Late October / early November | The winterizer — the most important feeding of the year. Roots store this energy for spring green-up |
The classic mistake: heavy early-spring nitrogen
A big March/April feeding makes the lawn look spectacular for six weeks — all top growth, shallow roots — then it limps into summer heat. If you crave a spring step, make it crabgrass pre-emergent instead (timing here).
Three rules that matter more than brand
- Water it in within a day or two of applying
- Never fertilize a drought-stressed or dormant lawn
- Sweep granules off pavement — that's pure runoff into storm drains
And remember mulched clippings count as a bonus feeding all season long (why we mulch by default).