How could labor unions get better wages for southern workers?

Labor Union were formed by workers in order to fight against unfair workplace conditions. One way that labor unions could provide better wages for Southern Workers is through labor strikes. The idea is that a group is better than one person. If one person goes to the boss and demands a raise it is highly likely that they will be fired. But if multiple people all go the boss and demand a raise they will mostly likely get it do the strength in numbers. If the workers go on strike then the boss will have to higher new workers to replace them or give in to the demands of the workers for higher wages.