I suppose you could wake them up with CFLs, give them a few hours of HPS, then lull them to sleep with the CFLs again.
Sounds complicated though.

It only tales a couple, three days to harden them to more light.
Just sneak up on 'em with the bright stuff.
And watch the temperature when you kick on that artificial sun.
Temperature is a big player in growth speed.

Aloha,
Weezard