Why does he hate me? He's away at college. Also blocked me from his phone.

Then leave him alone. Who is paying for his college?

If you are paying tuition and expenses, block him getting any more money from you!

I am sorry but there is not enough information given to know if he 'hates' you or if you are over-reacting to your child growing up and living his own life.

How is his relationship with other family members such as his father, grandparents, aunts, etc.? Do you have other children? Are there major conflicts in the family?

What do you mean by "blocked me from his phone"? Does that mean he blocked your calls/texts or blocked your access to the phone and information about his texts and calls? Do you call or text a lot? Do you get upset if he doesn't respond when you think he should?

How do you know he "hates" you? Has he said he hates you or is this your opinion based on his actions your own beliefs/thoughts?

As a mother, I know how difficult it can be to allow your baby the room and freedom to make their own decisions. Wanting to keep control even when they are out of the house and on their own can cause conflicts in ourselves and in our relationships. Have you added stress that is pushing him away?

If you are giving him financial aid (tuition, rent, food money, etc.), give him a list of reasonable expectations such as keeping his grades up, not getting arrested, be careful about family planning, and things like that. Make it clear that you are tying the financial aid to the conditions and then back off leaving him to live his life. Have him send you a copy of his end of term grades. Welcome him home wit open arms when he visits. Talk to him about other forms and times to keep in contact. If he doesn't show his grades/gets arrested/is becoming a father or actually says he 'hates' you, cut him off.

If you are basing your belief that he 'hates' you on his actions or by how he shows (or doesn't show) respect, check your expectations to make certain they are reasonable. If they are, talk to him. He is an adult and you should be able to communicate with him.

Mothers the world over cry "He won't talk to me on the phone!"
It means he's busy. It means he's learning how to be an adult, not tied to his mother's apron strings. It does NOT mean that he doesn't love you, and doesn't appreciate all you have done for him.

Parents who are paying for a child's education have a right to a certain amount of time on the phone, a quick hi and I'm OK and I love you.
5 minutes once a week is a LOT!
Next time you see him in person, negotiate something like that.
Let him grow, let him go, don't drive him away.