Nearly half of the synthetic fields surveyed in a new report are so worn they failed to make the grade - even though city officials have long trumpeted turf over grass for being easier and cheaper to maintain.
"Clearly more maintenance needs to be done," said Cheryl Huber, deputy director of New Yorkers for Parks, which released the study last week.
Of the 40 fields and playgrounds with artificial turf surveyed by the group over the past two summers, 19 were slapped with grades of D or F - mostly for having dangerous holes, loose seams and worn-out plastic blades.
Among the worst spots was Sternberg Park in Williamsburg, Brooklyn, where investigators found problems as far back as 2008 - just three years after the turf was installed, the group said.
"It's all torn up - home plate, the pitcher's mound. The situation's the same all over the field," said Ernesto Noble, 65, a retired school bus driver, who was warming up before a baseball game last week. "They need to send somebody to fix this place."
Nearby, pals Josh Diaz, 20, and Brian Montijo, 20, said the holes and torn seams were dangerous.
"It comes undone, it gets ripped up," said Diaz, as Montijo pointed out a gaping hole to the left of home plate. "I don't play as hard on this."
Wagner Playground in East Harlem - where investigators also spotted loose turf seams, missing or detached turf and worn away blades - failed two years in a row. It, too, was installed in 2005.
"The uneven surface can make you fall over when you play," said Mobido Sy, 11, of Harlem, who added that last summer he tripped on one of the field's loose seams during a soccer game and slammed into another player. "I got a cut on my head."
Other turf trouble spots highlighted in the report include Baruch Park and Sara D. Roosevelt Park on the lower East Side, Marble Hill Playground and St. Mary's Park in the Bronx and the Parade Grounds in Brooklyn's Prospect Park.
The city has installed the synthetic grass in 94 fields and 17 playgrounds across the city since 1998, the group said. Another 21 asphalt fields are slated to get the synthetic grass by 2013.
"The city keeps installing more, but they don't take care of the ones they have," said Geoffrey Croft, head of New York City Park Advocates, which has been critical of the city's push for artificial turf. "They are repeating the same mistakes as with grass fields, but this time it's much more costly."
City data cited in the report show that turf fields cost nearly double to install, though officials estimate that over time they save about $15,000 a year through reduced maintenance costs.
Parks Department spokeswoman Vickie Karp acknowledged "that several of our turf fields have shown wear and tear due to their age and heavy use," but said "maintenance crews make every effort to perform repairs."
In recent years, artificial turf has also come under fire for environmental reasons and for getting dangerously hot in the sun.
A Daily News investigation in 2008 found the turf can get as hot as 162 degrees on even a mild summer day.
Proponents argue that artificial turf stands up better to heavy use than grass and can be played on year-round.