The demonstrations are part of "Have a Heart Day," an effort to get the district to rescind many of its layoff notices before May 15, when the layoffs would take effect.
Matthew Hardy, spokesman for United Educators of San Francisco, said teachers distributed thousands of small buttons with pink hearts printed on them at schools throughout the city this morning.
Cards were handed out that asked parents to call district officials and ask them to stop the layoffs, which could affect about 1,000 teachers and support staff, he said.
"We think when parents realize the scope and scale of what's happening, they'll be deeply concerned and call the school district," Hardy said.
A handful of UESF members, as well as union president Dennis Kelly, also planned to donate blood at the Blood Center of the Pacific this afternoon. Kelly said the blood donations symbolize that "teachers are the lifeblood of the schools."
Miranda Doyle, a teacher-librarian at Martin Luther King Jr. Middle School, is one of those planning to give blood.
Doyle said that event is meant to show that "teachers are giving everything to their students." She said the pink slips issued in March have affected morale at her school and others around the district.
"Everyone's very worried that we won't be able to be back," she said. "We're very concerned but hopeful that many of (the notices) could be rescinded, and we hope by getting people out there that they'll support us and help us be there for our students next year."
Negotiations between the union and the district have stalled, and Kelly said "there isn't any real movement from the district on rescinding the layoffs."
The two sides met for mediation sessions on April 27 and Tuesday, and another session is scheduled for Monday, the day before the board of education will meet for the final time before May 15.
Kelly said union negotiators have proposed a concession package worth $27 million, including reducing the length of the school year by four days to save $14 million and parcel tax money making up the difference.
The school board has requested $44 million in concessions over the next two years to help bridge an anticipated $113 million deficit.
District spokeswoman Gentle Blythe said last week that the union had refused to consent to temporary concessions, including furlough days and the suspension of paid sabbaticals and some salary increases.
Blythe was not immediately available for comment today.
Teachers and staff will pass out more buttons and cards after school gets out this afternoon, Hardy said.
The blood donation event is scheduled for 3:30 p.m. at Blood Centers of the Pacific, located at 270 Masonic Ave.
Union members will also be holding four demonstrations at sites around San Francisco at 4 p.m.
The demonstrations will be near the intersection of 19th and Holloway avenues at San Francisco State University, at the 24th Street BART station, at the intersection of Market and Octavia streets, and at the intersection of Geary and Park Presidio boulevards, Hardy said.