What's wrong with my girls

Hi everyone. For some reason my w widows are curling at the bottom. They're about 6 days old, I keep them under 2 4' flourecent lights (blue and red spectrum) about 3 inches from them. Ph is at 6.9. temps at 83 degrees, 18 hours of light, water when soil begins to dry out and I'm using miracle gro with added perlite for drainage. Any help will be greatly appreciated.
Thanks,
Steve

i'm in hydro, but had similar problem earlier on, i moved the lights up a bit so they would stretch, and for veg i always used straight blue t-5s.