When is the optimal time to fertilize my lawn?
Written by
Nguyen Minh
Reviewed by
Prof. Martin Thorne, Ph.D.Finding out when to fertilize your lawn involves addressing your grass type, your climate, and legal parameters. For example, warm-season grasses like Bermuda need to be fertilized in late spring, while cool-season grasses such as Fescue benefit from being fertilized in the fall. To avoid overapplying fertilizer and wasting money, soil tests can help save you money, as I have seen countless clients waste hundreds on fertilizer since it was unnecessary.
Soil Analysis
- Test pH levels 6 weeks before planned fertilization
- Check phosphorus levels to comply with state bans
- Identify micronutrient deficiencies (iron, manganese)
Legal Compliance
- Verify county buffer zone requirements
- Review summer phosphorus restrictions
- Note winter fertilization blackout dates
There are unique issues that coastal areas must deal with. Notably, the Chesapeake Bay laws of Maryland prevent nitrogen application in winter and the coastal regulations of all of Florida prohibit phosphorus application in summer. Last July, a Naples client incurred $500 fines for ignoring bans during the rainy season. Research into the law of the regulatory agencies is as important as the agronomic aspects of lawn care.
The evolution of burning grass adds to the growing list of things to worry about when you use too much fertilizer. Excess nitrogen can seep into groundwater, with EPA reports indicating nearly 40 percent of residential drinking wells in fertilized areas have unsafe nitrate levels. I recommend slow-release products and calibrated spreaders as a good, sound practice to limit the impact of high nitrogen levels on the environment while still maintaining healthy turf.
Read the full article: When to Fertilize Lawn: By Region & Grass Type
