County commissioners' decision came after several hours' worth of public comment from those for and against the tighter rules.

Fertilizer can no longer be used for eight months of the year in Alachua County, starting in early October.

Tuesday night, county commissioners approved an eight-month ban on the grass treatment, a decision that came after an overflow crowd of lawn care industry members approached the board with a torrent of criticism about the proposed blackout period. Before, fertilizer was only banned the winter months of December through February.

The board unanimously agreed to pass the ordinance, which takes effect Oct. 1.

Business representatives asked the county to exempt lawn professionals from the fertilizer blackout period, saying landscape treatments aren't to blame for increased pollution in area waters.

“We’re not funding research to go out there and pollute, we’re going out to find out ways to not pollute,” said Andy Jorgensen, president of the Lakeland-based Florida Turfgrass Association. “Exempt the professionals, research the science, and then let’s talk about this down the road.”

The ordinance limits fertilizer usage from March to June, and insists that it be the slower-release variety, eliminating the chance that grass is saturated too quickly. The county’s environmental protection department said grass gets the most rain in the summer, so applying fertilizer then increases the chance of fertilizer runoff that bleeds into the county’s waterways.

U.S. Environmental Protection Agency reports say high levels of nitrogen in water cause algae blooms, as seen in the Santa Fe River. The department points to many sources, including commercial fertilizer.

“Every drop that escapes lawns is a danger to our springs and aquifers,” said the Sierra Club’s Cris Costello, who is based in Sarasota.

As one audience member said, the argument was not pro-water or anti-water, but rather, disagreements over ways to alleviate the glut of nitrogen and algae in the county’s waters.

“The springs are our red tide,” said Commissioner Ken Cornell. “That is my concern and in talking to many in the industry, that is their concern.”

Laurie Trenholm, an environmental horticulture professor with the University of Florida's Institute of Food and Agricultural Sciences, pointed out the department’s study of nitrogen rates showed turf does not account for large amounts of nitrogen runoff.

“Healthy, actively growing turf is not going to allow for loss of much of the nitrogen,” she said.

Trenholm said lawn care businesses should be exempted from the ordinance. County staff retorted that the IFAS study was conducted using near-perfect samples, unlike a typical North Central Florida lawn.

In 2011, IFAS was under scrutiny for a publication that argued that more restrictive fertilizer ordinances by local governments would likely have "unintended consequences," such as increasing fertilizer use other times of the year.

Many at Tuesday's meeting said the fertilizer ban would take the treatment process out of the hands of professionals and leave it to homeowners, who often mistakenly overuse the chemicals. They also added that without a fall fertilization period, plants will not absorb required nutrients.

Another UF faculty member argued just the opposite.

Francis Putz, an biology professor at the University of Florida, said turfgrass can only take in so much nitrogen before the chemicals overflow.

“You put a pound of fertilizer on, it goes somewhere,” he said. “If you have to fertilize every year, is your grass growing in biomass and getting gigantic and storing all that nitrogen? No, the nitrogen is growing somewhere: up, down or across in runoff.”

After more than 2.5 hours of public comment, commissioners decided to extend the months fertilizer could be applied to include March, in accordance with Environmental Protection Advisory Committee recommendations. To ensure residents understand and abide by the new rules, the county will hold two workshops with stakeholders, including lawn care professionals, to discuss how to enforce and educate homeowners.

Entities such as cemeteries, athletic fields, nurseries and golf courses are exempt.

Commissioner Mike Byerly said each side of the debate seems to have some uncertainty, but he sides with arguments to limit fertilizers.

“We don’t need beautiful chem lawns. It is a thrill, it is an aesthetic taste that is doing great harm to our state, in my opinion,” he said.