One of my good friends who is homeschooling spends about 3-4 hours/day on it, but I do think that a bit more than that is probably more desirable. Our local district "requires" you to do a minimum of 4 hrs/day, I believe, although I don't imagine that they'd be able to confirm how much time you are spending.

My goal, if we manage to make hs work next year for dd9, is to spend 4 hrs/day or maybe sometimes 5. I could wind up being wrong, though wink!

Study Strategies for Accelerated Learners