Start today. You can bush and floss daily, but if you have plaque that has hardened, it needs to be removed so that your condition does not deteriorate. See a dentist to get the best advice for your situation.
Ultrasonic/ laser ? Tartar becomes imbedded in the roots of your teeth at a cellular level. You cannot not brush this away. This calcified, embedded plaque must be removed. If you deplore hand scaling, ask your dentist about ultrasonic therapy ( gentler scaling) or maybe laser therapy.. But this tartar must be removed some how.. Ask your dentist about using nitrous oxide or oral sedation for your appointment.
How deep is it? Gingivitis is a shallow disease of the gumline. If your teeth have sharp, infected, tartar crusting on them like barnacles, there is nothing except scaling that will help your gingivitis. If your teeth are clean and you still have it, ask a professional to help you do a better job of brushing and flossing.