San Antonio Mayor Julian Castro is trying to sell us on a $0.08 sales tax increase that would go to early education programs in the city.

He says the average household will spend less than $8 a year on the hike.

That hike is expected to raise $31 million a year, benefiting more than 22,000 kids.

It seems like a worthy investment.

However, if any effort to improve education is going to stick, there has to be some accountability -- starting at home.

The plan is supposed to require parents to read to their children, help with homework and attend regular parent-teacher conferences.

But parents are already supposed to be doing this.

How can we realistically expect, track or enforce any real accountability going forward?

Tax money alone can't solve children's education.

Parents also need to step up for their kids and spend not just money but time to make a real difference.