The Blue School is one big play date in desperate need of adult supervision.

Parents are yanking their kids out of the “progressive,” $32,000 per-year private school founded by the Blue Man Group — which has no books and no tests — because their kids are barely learning to read, The Post has learned.

One mother, who is yanking her son at the end of the school year, complained that the school is “unstructured.”

“It’s true,” she said when asked if her kid was struggling to read.

In all, she added, four of her son’s first-grade classmates are leaving the Financial District institution.

Another parent who dropped her first-grade son off yesterday said he’s not coming back next year — because he’s got nothing to do.

“When a 6-year-old says they’re bored, there’s a problem,” the mother said. “I think they bit off more than they can chew.”

Other moms have taken to a popular message board to vent.

“It’s all fun and games until you realize your second-grader can’t read,” a parent wrote on Urbanbaby.com.

And parent Marina Brolin added, “I think they don’t push [reading] as much.”

Earlier this year, parents complained that their students weren’t ready to take tests, so third graders were given private school admission practice exams.

“You’ve got to give kids some experience with testing,” admitted Don Grace, the interim head of school.

Eight teachers are leaving the school at the end of the year — and the head of school will be replaced in July with public school veteran Allison Gaines Pell, who founded the Urban Assembly Academy of Arts & Letters.

“We’re going to try to decrease the attrition,” Grace said, explaining one of the teachers is moving. “One of the things we’re going to do next year is going to look at teacher attrition.”

The Blue School, founded by members of the theater troupe and their wives as a play group in 2006, got its independent-school charter in 2009.

The school holds an annual fund drive for parents — 72 percent contributed during the most recent one, officials said.

School officials say students decide their own curriculum, and have no set arrival time. Grades run from kindergarten to third grade. A fourth grade is being added next year.

Some experts said parents who choose progressive schools shouldn’t expect to see the same results as they do from a conventional school.

“A majority of my Upper East Side clients, if they took a look down there, their heads would explode,” said education adviser Terri Decker of Smart City Kids. “Literally, their brains would be on the pavement.”

There will also be a new position created next year to pave the way for Blue School kids to get into other independent schools, like Horace Mann and Calhoun School.

“Parents are understandably anxious about being patient if their child is developing at a slightly later time,” said Steve Nelson, head of the Calhoun School, who advised parents to remain calm.