A foundation run by the heirs of Wal-Mart founder Sam Walton plans to spend $1 billion on public schools over the next five years.

The Walton Family Foundation planned to notify patrons Thursday that it hopes to establish new charter schools and help programs already in place. The money will be spent in about two dozen states where it has already aided programs.

Charter schools are privately run but receive public funding. Many are dedicated to the arts or to science and technology.

The National Education Association, the nation's largest teachers union, says charter schools have produced mixed results and that a billion dollars could go a long way if given directly to traditional school systems.

The Walton foundation has spent $385 million on charter school start-ups since 1997.