well no ones posted. probably because no one has every had a problem with there grow being too cold. it's always too hot

so maybe your lucky

What temp are your seeds at?
If you only have 1 CFL your problem is probably not temp but insufficient lighting.
1 23W CFL only puts off 1600 lumens. You want at least 5100 lumens/sq foot. So really you only have enough light for like a few sq inches