Garza said fury over Brown's killing resonates with anger over recent officer-involved shootings in the Bay Area.
"In Oakland in particular, many people are still outraged about the murder of Oscar Grant," she said.
The fatal shooting of Grant by BART police Officer Johannes Mehserle in 2009 sparked heated protests in Oakland and skirmishes with police that flared again when Mehserle was convicted of a lesser involuntary manslaughter charge, and again at his sentencing.
Grant's mother, Wanda Johnson, said she plans to go to Ferguson soon to support Michael Brown's family.
"I look at Oscar’s case and I look at Michael Brown’s case and see similarities," she said. "First it’s taken this long to bring up any charge against the officer. Second, every day there’s something new developing with why he shot this young man, same thing with Oscar. Then you go through a phase of demonizing the young man who was shot, same thing with Oscar."
Black Lives Matter is seeking to change what the group says is a "systemic pattern of anti-black law enforcement violence in the U.S." Other demands include disarming police of weapons handed down from the military, releasing the names of officers involved in killings, and redirecting law enforcement spending to impoverished African-American communities.
Garza said the next steps for the group will likely be determined this weekend, but she hopes the message will spread out across the country.
"So that we make sure that places like Ferguson, Missouri, are not isolated from places like Oakland, California, or places like Chicago, Illinois," she said.
A spokesman for St. Louis County Police said law enforcement agencies in Ferguson are aware of the gathering planned for Labor Day weekend, but they're not commenting on what the police response may be.
St. Louis County arrest records list 218 bookings related to Ferguson protests between Brown's shooting on Aug. 9 and Aug. 23. The majority are misdemeanor refusal to disperse charges, with other arrests for burglary and possession of possible burglary tools, receiving stolen property, unlawful use of a weapon, trespassing, assault, disorderly conduct, resisting arrest and outstanding warrants.
KQED has been able to confirm that four of those arrested listed a California city of residence, and all four were for refusal to disperse. One is from San Francisco, one from Pasadena, one from Valencia and one from San Diego.
Johnson said despite the difficulty posed by looters and people seeking to commit other crimes, protesting killings by police is necessary, in the Bay Area and Ferguson.