In case of the 529 plans in Pennsylvania, your fund either goes one hundred per cent into the stock funds or shared in the ration of 4:1 in favor of stocks and bonds. In either case there is an increased investment towards stock funds. Even among this, there is an inclination towards socially responsible portfolios rather than money market portfolios. This is possibly the reason why 529 plans in Pennsylvania seem to provide you the necessary growth with the increasing college fees over a period in time. If you do not want to risk your investment but would rather bid for a guaranteed return, then too you can subscribe to one of the 529 plans in Pennsylvania, Guaranteed Savings Plan.
More on 529 College Savings Plans and Collegeamerica 529