New York City Mayor Bill de Blasio is cultivating a new group of pre-kindergarten advocates: parent bloggers.

He invited 20 of them to City Hall today to ask him questions about his plan to expand pre-K and middle-grades after-school programs using a tax on the city’s highest earners. The unusual event was intended to get the parents to rally their substantial audiences to press for a swift expansion at a time when de Blasio’s funding plan has gotten little traction in Albany.

“People respect your voices and I think they need to hear your urgency,” de Blasio told the bloggers. “Our friends in Albany … need to hear parents say, ‘Great, have your differences, but we need this in September.” And I think if your voices are heard, I think the decisive moment will be realized and it will be a transcendent moment for our schools.”

The parents came from four boroughs; have children in public, private, and charter schools; and largely have not made education policy issues a focus of their sites. They were less interested in the politics around the pre-K push than the formidable logistical challenges involved in opening new programs and on the experience that the programs would provide for families.

Serena Norr, the mother of a student at Cobble Hill Success Academy charter school and an editor of the site Momtrends, asked how de Blasio would find enough space for pre-K programs when crowding has caused some elementary schools to close their own.

Liz Gumbiner, who runs the site CoolMomPicks and whose children attend P.S. 8 in Brooklyn, asked about how de Blasio would ensure quality without testing pre-K students.

“What are the plans to measure outcomes for these programs so they keep their funding without what I think is kind of an immoral amount of pressure put on very young children?” Gumbiner asked.

And Matt Schneider, a former teacher who runs the site NYC Dads, asked whether the city would change enrollment policy to guarantee kindergarten spots for children who attend pre-K at that school.

While officials from City Hall and the Department of Education had answers about testing and space concerns, Joshua Wallack, who recently joined the Department of Education to steer pre-K implementation, said he would have to learn more about the city’s enrollment systems before responding to Schneider. (Chancellor Carmen Fariña was not at the meeting.)

“As far as the enrollment processes, I am on day five of the job,” Wallack said, adding, “It would obviously be better if it was a seamless system.”

De Blasio’s preferred strategy to fund the pre-K expansion, a tax on the city’s highest earners, does not not have support from Gov. Andrew Cuomo, who has proposed increasing pre-K funding statewide. Polls suggest that New Yorkers side with Cuomo, but just weeks before this year’s state budget must be set, de Blasio is continuing to argue that only a tax will allow for the quick expansion of programs that he says parents want.

Yet the very first question suggested that not all parents are as eager to sign up for the new programs as de Blasio has promised.

“Are these programs going to be optional or mandatory?” asked Kimberly Coleman, who writes the blog Mom in the City. “Because there are many people who want these programs but also people who have strong feelings about that time they have with their kids and want more family time.”

De Blasio assured Coleman that both programs would be optional. “We know that many people have different approaches they want to take,” he said.