It's time for Hillary Clinton to start worrying about her Florida campaign.

Despite roughly 500 full-time staffers spread across the state to help Clinton win forever-close Florida, party leaders and activists are fretting about the campaign's ground game. Even Clinton staffers in other states are quietly buzzing about the Florida campaign struggling to meet its goals for voter registration and other outreach benchmarks.

"There needs to be more of a presence," said Ken Welch, a Democratic county commissioner in Pinellas County. "I haven't seen it yet in the places where I would expect to — churches, even Little League games. You absolutely saw that four years ago with the Obama campaign."

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"The adjectives I would use are underwhelming and stressful," said Monica Russo, president of the SEIU Florida service employees union, of the campaign's voter outreach efforts.

U.S. Rep. Alcee Hastings, D-Delray Beach, has already let leaders of the Brooklyn-based Clinton campaign have it for not focusing enough on grass roots organizing — "If you spend $20 million on television, and you don't move the needle, then you need to recalibrate" — and is confident they got the message.

"I had a conversation with a kid in Brooklyn, and I said, 'Well how is it you're in a position to know more about turnout than I do?' He told me he had a master's in political science," Hastings recounted. "I said, 'Well, I have won more elections than you spent time in school to get your master's.' "

Florida polls show a dead-even race, and the Clinton campaign insists it is well positioned.

"I have zero concern," said Marlon Marshall, Clinton's director of state campaigns, dismissing talk among Democratic operatives that the campaign has had to dramatically scale back its goals for voter registration.

"Our team is doing a great job. As the person who knows our marks, we're hitting our marks. If you look at the (voter) file comparing today to 2012, there's actually 134,000 more African-Americans on the file and 364,000 more Hispanic voters," Marshall said. "We're actually ahead of where I thought we would be right now."

Other Democrats say the Clinton campaign recently dispatched a senior organizer from Virginia to help shore up the Florida effort, but Marshall said the campaign is beefing up senior staff in several battlegrounds besides Florida, including Iowa and North Carolina.

Some of the raw numbers in Florida are hardly encouraging for Clinton.

President Barack Obama, campaigning with an enthusiastic Democratic base behind him and a campaign infrastructure built over 15 months, won Florida by less than 75,000 votes in 2012 when the state had 536,000 more registered Democrats than Republicans.

Clinton, who by all accounts has a less enthusiastic base behind her, started building her campaign much later and faces an electorate where the Democratic voter registration advantage has shrunk to 274,000.

Four years ago, voter registration efforts led by the Obama re-election campaign helped register about 375,000 Democratic voters in Florida, and Democratic strategists early this year talked about trying even to exceed that in 2016. Marshall would not say what the current target is, but other Florida Democrats say that goal was cut in half by last spring and still more subsequently.

From May through August, Democrats added 96,000 voters to the rolls compared to 81,000 for Republicans. The deadline to register to vote for this election is Oct. 11, and registrations typically surge as the deadline approaches.

More than half the vote in Florida is likely to be cast by Election Day on Nov. 8, and there is encouraging news for Clinton on that front.

A record 2.5 million Floridians so far have requested mail ballots, and according to an Associated Press analysis, Republicans are ahead in ballot requests, 43 percent to 38 percent. That's a narrower gap than in 2008, the most recent for which comparable data is available, when Republicans led 51 percent to 32 percent.

No one can accuse Clinton of taking Florida for granted.

Today, the Democratic nominee is scheduled to campaign in Fort Pierce in St. Lucie County and Coral Springs in Broward. Bill Clinton was scheduled to campaign across North Florida today and Saturday but had to cancel to attend the funeral of the former Israeli President Shimon Peres. Vice President Joe Biden is scheduled to campaign in Sarasota and Orlando on Monday. And President Obama is scheduled to speak at USF in Tampa on Wednesday, an official event.

One night recently, the Times stopped by unannounced at Clinton's Ybor City campaign office in Tampa. About eight staffers were present, offering up campaign signs, working phones and hunched over laptops.

From there, we went to Trump's Tampa office near Kennedy and Dale Mabry. At 8:30 p.m. it was closed tight, a cardboard cutout of Trump peering through the glass front door set back from a locked front gate.

Both sides are boasting muscular turnout machines.

The Trump campaign was late organizing a get-out-the-vote program in Florida, but the Republican National Committee has been working at it for two years.

"It's the largest, most robust presence we've ever seen in Florida," said Susie Wiles, who is running Trump's Florida campaign. She said more than 200 full-time staffers and about 1,000 paid, specially training organizers are working to deliver Florida to Trump. Including active volunteers, "the army of Trump is 70,000-plus people in Florida."

"We are on par to walk a million and a half doors the last week of the campaign," she said.

Between national, county and Trump offices, Wiles counted about 60 offices, comparable to the 65 Clinton campaign offices. On top of that, the rapidly growing Clinton campaign staff currently totals about 500, and a Democratic super PAC, For Florida's Future, has at least 200 full-time staffers working to deliver Florida.

Still, Democrats question whether the so-called Obama Coalition — young voters, minorities, college-educated whites — will turn out for Clinton.

"I don't get a sense that folks are as excited about the first woman president. We ought to be as excited to support that, but I don't see it yet," said state Rep. Darryl Rouson, who represents several heavily African-American neighborhoods in St. Petersburg. "They really need to ramp up the grass roots."

But former Hillsborough County Commissioner Tom Scott, a prominent pastor in Tampa, said not only did former President Clinton meet privately with him and dozens of other African-American pastors recently, but he met with Hillary Clinton recently, and a Clinton campaign canvasser knocked on his door the other day in east Tampa.

"I think you'll have a good turnout this year with African-Americans, but not as much as Obama. Obama was African-American. You had these guys determined to make him a one-term president, and black folks turned out," Scott said. "The black vote is going to be more anti-Trump than pro-Hillary."

Times staff writers Jeremy Wallace and Alex Leary contributed to this report. Contact Adam Smith at asmith@tampabay.com. Follow @AdamSmithTimes.