Unions in the Twin Cities and their allies are planning to kick off a series of strikes and protests on Black Friday, billed as the busiest shopping day of the year.

Janitors who work for companies that clean Home Depot, Best Buy, Kohl’s, Target and Sears will strike unless their employers agree to negotiate with the Service Employees International Union.

Other workers plan to march on University Avenue in St. Paul to protest poverty wages on Friday, while fast-food worker protests and a demonstration by airport workers are scheduled for Dec. 4 and Dec. 5.

After organizing home health care workers this summer, one of the largest successes in labor’s history in Minnesota, the SEIU and the worker center CTUL, which stands for Centro de Trabajadores Unidos en la Lucha, are trying to build momentum for unions of airport workers and janitors, among others.

The most substantive event planned in the next 10 days is the strike by retail janitors, which was first threatened earlier in November. About 50 workers seeking higher wages and benefits and the right to form a union have committed to the strike, and plan to meet early Friday morning near the Target and Home Depot just off Interstate 35W in northeast Minneapolis.

“They’re still treating us like we’re invisible,” said Luciano Balbuena, 54, who works for a company named Kimco Services and cleans the Home Depot in Richfield for $9 per hour. “If they don’t listen to us, we’ll have to continue to keep doing strikes.”

Kimco Services could not be reached for comment Tuesday.

Janitors in the Twin Cities and CTUL won a victory in June, when Target Corp. created a “Responsible Contractor Policy” that requires companies contracted to clean Target stores to engage with workers to improve working standards in the industry. CTUL had protested Target several times.

Many other retailers haven’t adopted a similar policy, however, and CTUL said the companies that clean Target stores — Carlson and Prestige — have not engaged with workers to their satisfaction.

Worker centers like CTUL have begun to irk some businesses because of their resemblance to organized labor and close ties with unions like the SEIU. But the National Labor Relations Board concluded in 2006 that one large worker center, the Restaurant Opportunities Center, was not a union.

Airport workers who work for AirServ at the Minneapolis-St. Paul Airport have scheduled a protest for Dec. 5.

The SEIU Local 26 is trying to organize hundreds of airport workers, many of them East African, who clean plane cabins and help disabled passengers get through the airport. Some of the workers are also seeking to be paid $15 per hour.

“I only make minimum wage assisting elderly and disabled passengers for contractor AirServ,” said Darcy Landau, a wheelchair assistant for AirServ, in a statement. “I am proud of my job and I enjoy helping seniors but I am still unable to plan for my own wedding or even make basic steps forward in my life due to the low wages.”

It’s not clear how many airport workers support the SEIU’s efforts.