A federal appeals court Wednesday overturned the pot-growing conviction of the self-proclaimed "Guru of Ganja," a marijuana advocate who has written books on how to grow pot and avoid getting caught.

The court cited jury misconduct in overturning Ed Rosenthal's conviction, but it otherwise upheld federal powers to charge marijuana growers.

Rosenthal was convicted in 2003 for cultivating hundreds of marijuana plants for a city of Oakland medical marijuana program. U.S. District Judge Charles Breyer sentenced him to one day in prison, saying Rosenthal reasonably believed he was immune from prosecution because he was acting on behalf of city officials.

The government sought a two-year prison term and appealed. Rosenthal cross-appealed.

The case drew national attention, in part, because of Rosenthal's status as a leading author and proponent of marijuana. It also underscored the federal government's position that medical marijuana is illegal, it has no medical value, and the will of California voters has no affect on federal drug laws.

A three-judge panel of the San Francisco-based appeals court, in overturning the verdict, said a juror had had inappropriate communication with an attorney.

"Juror A" had asked a friend who is an attorney whether she had to follow the law or could vote her conscience because she suspected Rosenthal was growing marijuana for medicinal uses. The attorney told her she must follow the judge's instructions to follow federal law or she would get in "trouble."

"We hold that here the communication was an improper influence upon Juror A's decision to acquit or convict," the appeals court wrote.

The court rejected Rosenthal's argument that he should have been allowed to tell jurors he was growing marijuana for the city for medicinal uses.

While the case was on appeal, and despite Rosenthal's claims, the Supreme Court ruled again that the federal government can prosecute medical marijuana growers and users despite California's medical marijuana law.

Rosenthal once wrote the "Ask Ed" column for High Times magazine and has written books with titles including "The Big Book of Buds" and "Ask Ed: Marijuana Law. Don't Get Busted."

Reached by phone Wednesday, he declined immediate comment on the ruling, saying he had not yet read the decision.

U.S. attorney's spokesman Luke Macaulay said the office was considering whether to appeal or going ahead with a new trial.