If your African Violet gets a long neck or stem what you will want to do is re-root it. Using a sharp blade or your fingernail scrape the stem to expose the inner tissue. Put a bit of rooting hormone on the stem.
Now you will want to bury the stem in the soil. You will more than likely need to cut off some or even all of the root ball. The buried part of the stem will begin to produce new roots.
You will also want to remove all of the blossoms so all of the energy goes to forming the new roots.
