Can someone tell me how long will osgood schlatters take to heal?

Comes and goes: Generally occurring during adolescence, when growth is done, the area at the tibial tubercle will most often fuse with the rest of the tibia. At times, there may be fragmentation of the "bump" and it can become recurrently painful, and at times can benefit from having the loose fragment taken out.

Osgood Schlatter: Osgood-schlatter is a condition involving a portion of the tibial growth plate at the insertion of the patellar tendon. It is associated with tight quadriceps (especially the rectus femoris). There can be a painful fragmentation that occurs at this area. The best treatment is lots of stretching, nsaids and rice. It resolves when the growth plates close (around 14 for girls, 16 for boys).