The amount of time it takes for dreads to lock up varies significantly based on hair type and choice of method. Also consider that the term “lock up” means to get knots established in your dreadlocks whereas the term “mature” refers more to when your dreadlocks are very well established and fully tightened.
Kinky hair types lock up the easiest whereas straighter hair types take more effort and care.
For twist and rip, backcomb, palm rolling, and free form methods you should expect 12-18 months to lock up and reach maturity.
Interlocking, in some cases never locks up properly for Kinky hair, which mainly depends on how skilled your stylist is with interlocking. For straighter hair types interlocking never fully locks up, it just creates a braided or giant knot effect in your hair that is not truly a dreadlock.
For twisting in Kinky Afro hair the timeframe is typically 6-12 months. Mixed races will experience a longer timeframe with this method. Twisting in Straighter hair types typically falls out within a day or two and is highly discouraged for straight hair types.
For the crochet method your hair is locked up on day one for any hair type! It’s literally instant. This method will also produce the quickest route to fully mature dreadlocks.