Root Riots, etc work best in a domed growing tray. Without, spray them with water every day to keep the just moist and they'll work great. Adding a little water to the tray helps also.
I've been doing direct to soil also and I've found the results though mostly good, inconsistent. overall, I still find the paper towel method the best of germination rates, with Jiffy plugs ( same as Root Riots and Monsanto doesn't own them.... ) a close second.