In order to force budding you have to put them on a 12/12 light cycle and make sure no light hits them during the dark part of the cycle... oh wait... no thats something else.
Seriously though, you can cut them in half or even quarters to "force" them to split. I have done this alot and they are usually healed and back to the size they were when you cut them in a 3-6 weeks or so.