I have like 4 inches of straight hair at my roots! Why did this happen and how can I fix it? - Dreadlocks FAQ's
Depending on the amount of hair in the sections, their location and your hair type, dreads will likely need a little maintenance in order to continue locking as the hair grows. Some Lock Blockers continue to perpetuate the myth that no intervention is necessary. Certainly in some situations that is true, but anyone that has found their dreads hanging from several inches of straight hair after not doing maintenance for a long while can tell you that it doesn't hold true in all situations. Since we don't all have the same hair type and were not all growing the same size dreads it makes sense that the maintenance we'll need to do will vary from person to person.
Keep in mind that even when new growth is fully maintained you'll have 3/4" to 1" of straight hair at the roots. That's just how dreads are. Most people that have never been around or had dreads themselves think dreads go right down to the scalp. Silly straight hair people. =]
The more hair you have growing into a dread the easier it is for them to lock on their own. With curlier or more textured hair types you can get dreads with less hair to lock on their own. If there were no way to help hair lock as it grows you'd be forced to choose sections that were large enough to lock in your hair type without any intervention. For most people this would mean getting pretty large dreads, probably a lot larger than they had in mind. This can have downsides of it's own. For example, if you must have larger sections the number of dreads you can have is reduced which can make dreads look sparse. Large dreads also dry slower which can be a pain, especially if you have an active lifestyle.
Fortunately it's pretty easy it help the new growth dread just clockwise rubbing the roots and keeping the hair free of soap residues. Most people don't mind a little clockwise rubbing now and then and as a result they can choose from a much wider range of dread sizes, even in very straight hair types.
In addition to size and hair type, location also plays a part in how much help new growth will need to continue locking. Because of how we move around when we sleep and where our heads contact the pillow you'll often find that dreads of the same size in different areas of your head may lock up with less intervention than others. How much hair you have (per square inch) also varies from one area of your scalp to another. Areas with less hair will likely produce smaller dreads that need a little more help. You can compensate for this when you're planning your sections by trying to vary the section size as needed to keep the amount of hair in each section consistent.
Even though it's possible to make tiny dreads, 1/2" sections or smaller, and get them to lock it's usually a good idea to make them at least a littler larger than that in most hair types. Having a little more hair in each dread will make all maintenance a little easier and each dread will also be a good bit stronger.
Four inches is a lot of new growth. Most people end up taking care of it sooner but sometimes it just happens. You can still create knots in by clockwise rubbing but there are a couple challenges. For one, the knots will form in less predictable ways. You might end up with it wanting to knot up into two strands instead of one. Having some Locking Accelerator dry in the hair before you begin clockwise rubbing will help with this. Keep a close eye on the knots as they form and try to help them into a large ball-like shape. Later the ball will stretch out become more dread-like as you palmroll it, but as it's knotting it will be way more round. Having a Lock Sculpta on hand to pull hair into the wad and bring things together will help a lot too.
The other big challenge is preventing it form knotting up with the surrounding dreads. In most cases the unknotted new growth and heaps of loose hair will be common to all the dreads. The easiest way to keep the hair you're knotting away from surrounding sections is to take an old t-shirt, or similar material that doesn't shed and make a small hole near the center. Then you can pull the dread and all the loose hair that needs to go into the dread through the hole. Tie the rest of the shirt out of the way and you'l have a great surface you can clockwise rub against with no chance of dreading multiple dreads together.
After you have a nice big wad of knots pallroll them and help them compress. You can use the Lock Sculpta to help tidy things up a bit and pull in stray hair. If you find any mobs of straight hair at the roots that didn't make it into the dread you can pull them in with a loose hair tool.
That should pretty much take care of it. Try to get in the habit of clockwise rubbing the new growth a little as it grows. It will be easier when it's not so long and you'll have less loose hair at the roots since new hair that's first growing out will be more likely to get tangled in with the roots of the dread above it.