When should I fertilize my lawn?

Question:

When should I fertilize my lawn?

Answer:

Most lawns in Iowa are comprised of Kentucky bluegrass and other cool-season grasses.  Cool-season grasses grow best in spring and late summer/early fall when environmental conditions are usually favorable.  Applications of fertilizer should coincide with favorable growing conditions.  

In Iowa, cool-season lawns can be fertilized in spring (April or May), mid-September, and late October/early November.  High-quality lawns would be fertilized at all three times.  A minimally maintained lawn would be fertilized in late October/early November.   Moderately fertilizer programs would have applications done in mid-September, and late October/early November. 

Do not fertilize Kentucky bluegrass and other cool-season grasses during the summer months (June, July, and August). 

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Last updated on
June 24, 2025