When to use des

Question

I'm unsure of when/how to use desIf I want to use des as in the plural indefinite article, like des carottes would it be:J'ai besoin des carottes - I need some carrots. Or would that sentence translate as: I need THE carrots because de+les= des?

Accepted Answer

J'ai besoin de carottes. -- I need carrots.J'ai besoin des carottes. -- I need the carrots.J'ai besoin de ces carottes. -- I need these carrots.
Verbal phrases like avoir besoin de don't use the definitive article (or partitive article). If you add les, you are talking about specific carrots. This is different in other phrases, which don't already include de, such as:
Il me faut des carottes. -- I need some carrots.