The Big Ten announced kickoff times for homecoming games this morning, including Ohio State's. The ESPN Big Ten blog reports that the Buckeyes will face Rutgers at 3:30 PM, on Oct. 18th.
That leaves just six games on Ohio State's schedule where the kickoff time is still TBA: Kent State on Sept. 13, at Maryland on Oct. 4, at Michigan State on Nov. 8, at Minnesota on Nov. 15, Indiana on Nov. 22, and Michigan on Nov. 29. I'd guess that Kent State is likely to be an earlier game, and we know Michigan isn't going to be under the lights.
But the Buckeyes will have plenty of opportunities to play night games this season. Ohio State has four currently on the schedule, with Sept. 6 against Virginia Tech being the first, an 8 p.m. kickoff. Cincinnati on Sept. 27 will be a 6 p.m. kickoff, and a Nov. 1st home game against Illinois will also kickoff at 8 p.m.. Ohio State's lone road night game will be against Penn State, on Oct. 25.
Rutgers will likely have a few losses on the schedule before they face Ohio State for homecoming. They open the season at Washington State, and will play Penn State and Michigan, as well as road game against Navy, before facing the Buckeyes. The Scarlet Knights will have the benefit of an off week to prepare for Ohio State though.