Congress postponed approval of a D.C. school voucher plan yesterday until at least next month, causing concern among federal officials and voucher advocacy groups that they are running out of time to get the program launched by next fall.

The $ 13 million initiative, part of a $ 328 billion federal spending bill, would provide taxpayer-funded grants of up to $ 7,500 to at least 1,700 low-income District children to attend private and parochial schools.

Although House and Senate negotiators completed work on the bill yesterday, Congress recessed for Thanksgiving without voting on it. The postponement was triggered by prolonged disagreements involving Democrats, Republicans and the White House on issues unrelated to school vouchers.

The House is scheduled to return Dec. 8 to vote on the spending bill; the Senate plans to return Dec. 9, Majority Leader Bill Frist (R-Tenn.) said. If lawmakers fail to pass a spending bill then, Congress would have to act between Jan. 20, when it returns to session, and Jan. 31, when a stopgap spending measure runs out.

Voucher advocates said the delay makes it more difficult to start the five-year voucher program next fall.

"December is pushing it," said Kaleem Caire, D.C. voucher project director for Fight for Children, a Washington education advocacy group. "January is almost too challenging."

The legislation calls for the U.S. Department of Education to hold an open competition to select an organization to administer the grants. The grant administrator will then need time to reach out to parents and recruit private schools to participate. The administrator would set eligibility standards and guidelines for determining voucher amounts.

Voucher students ideally should be selected by June 21, said Nina Shokraii Rees, deputy undersecretary for innovation and improvement at the U.S. Department of Education. But the process of selecting a grant administrator normally takes several months, Rees said.

"To do it well takes time, and I don't know of any grants that we've been able to turn around in less than a few months," Rees said. "[But] you certainly don't want to run into a problem when parents are notified in the summer, and they don't have a lot of time to go and look at the schools they want to send their students to."

Officials at private and parochial schools said delays in starting the program could lead to conflicts with their admissions calendars.

Educators said they expect most voucher students to attend schools run by the Archdiocese of Washington. Those schools generally charge less for tuition and have more openings than private independent schools in the District. The archdiocese's high schools plan to send out acceptance letters Feb. 27 for students entering in the fall.

"Some principals might set aside a number of seats if they know there would be vouchers ahead of time," said Susan Gibbs, spokeswoman for the archdiocese. "I anticipate they would take that into account in the process."

Elizabeth Downes, executive director of the Association of Independent Schools of Greater Washington, which has 25 members, said the schools typically send out acceptance letters in March. She said she doubted that they would set aside slots for voucher students chosen after that.

Aides to District Mayor Anthony A. Williams (D), a supporter of vouchers, had planned to meet with Downes's group this week to talk about the program. Now they are scrambling to reschedule the meeting because of the congressional delay, said Gregory M. McCarthy, a deputy chief of staff in the mayor's office. Other meetings will be held with private school principals, parents and the general public, McCarthy said.

One of the challenges that voucher advocates anticipate is finding enough openings at private high schools for voucher students. The legislation gives priority to 8,700 students at 15 low-performing D.C. public schools, 5,200 of whom attend seven high schools. A survey by Caire's group found that only about one-third of 3,259 vacancies at 30 archdiocese schools and 31 non-Catholic private schools in the District are in the upper grades.

Staff writer Justin Blum contributed to this report.