Charlotte County has joined Sarasota County and a handful of Southwest Florida cities in regulating fertilizer application to protect water resources.

The new law, passed by the County Commission on Tuesday, requires residents and lawn maintenance professionals to limit the amount of fertilizer they use and rely more heavily on slow-release products.

"It's a good step in the right direction," said Jim Thomson, director of environmental extension services for Charlotte County. "It isn't where we were yesterday. Yesterday we didn't have a fertilizer ordinance. Today we do."

Commissioners were set to vote on fertilizer rules similar to those Sarasota County passed recently, but instead made some last-minute changes.

They eliminated a fertilizer blackout period that would have prohibited fertilizer application during the June-through-September rainy season.

The original proposal also would have prohibited fertilizer use within 10 feet of a water body. It was changed to reduce the setback to 3 feet if a shield is used during application.

Beach residents and Sierra Club members supported adoption of the law, which generated some opposition from fertilizer and pest management workers.

Suzanne Graham, who owns American Pest Control in Charlotte County, said she opposed the new law's licensing requirement.

Lawn care companies must now be certified in Charlotte or Sarasota counties and be trained on how to best apply fertilizer to reduce pollution.

The class costs $25, Thomson said.

Fertilizers are often cited as a source of nutrient pollution in waterways. Nutrients grow grass, but when too much is applied the grass cannot absorb it all. Excess fertilizer that washes into waterways can encourage algae growth.

Thomson said the new law will involve educating residents about proper fertilizer use. A series of mailings will help spread the word.

All but one commissioner, Adam Cummings, voted for the ordinance.

Cummings withdrew his support after the other commissioners reduced the setback and eliminated the blackout period.