Those are a curly hair problem in general. The problem is that the individual strands curl around themselves, to form the knot. It's just one of those things that comes with the territory. As for not wanting to cut your hair, I understand. But in my experience these knots can lead to breakage and split ends, which would be counterproductive to your length retaining efforts.
Your best option may be to do a search and destroy once a week or however often you feel it's necessary. Find them and cut just above the knot to get them out. It's time consuming and may require traveling with well stored shears, but worth it. HTH