I have always wanted dreadlocks. Well right now is the time in my life where I will be able to get them, and MY hair is just past ear length. I want to get them before I graduate college (hopefully). I'll keep coming here as a "how to" place so i can get my dreads perfectly.
About 15cm is fine for backcombing, when going natural I have no idea, probably shoulderlength to get anything going. With these lengths the dreads will be rather short though, they wont even be as long as your hair.
Yeah if you start them really short you do get a kinda of pineapple motiff going on.. But i know people who started it so short that after backcombing they literally had 2 inch spikes all over their head.. By the time they got to like ear length they looked awesome.. they were quite easy to maintain apparently!
usually if you have to ask if you have enough hair you dont, but you need around 15cm or 6 inches of hair, without using wax because wax is the devil, or else there is a very large chance they will just fall out.
Well you CAN do it at any length really. When you backcomb them expect to lose almost 50% of the length. I had mine combed in when my hair was like 8-9 inches long and honestly I waited too much. It took forever to comb in (which it will take anyway) and longer to lock up. In retrospect I should have done them earlier and just let them grow in. I would say 6-7 inches is a good place to start.