as long as they have heat to thermoregulate was the advice that i got. from experience i'd say a regular uva basking bulb (approx $6-9 at the petstore) will get more of a responce. i had a uva bulb, but accidentally spilled water on it and it busted.
scary stuff, the pop was loud, too. i used a regular incandescent bulb, but there was a noticeable decline in their activity and they went back to the burrowing. the next day i bought another uva bulb and they got right back up.


that happened less than five minutes after i switched out the bulbs, i am not exaggerating.
one of the texts i read said it's best not to handle a turtle too much... 15 minutes a day is less stressful than one hour in one day. so if you can get them a little sunlight so they can get some uvb that will be good. make sure the weather is warm, though. min. 70 degrees, sunny, no drafts. that was what i was told.
oh and just as an fyi - i would highly recommend keeping gravel OUT of their tank. that setup was when i first got them and lasted only three days. i only used gravel b/c i didn't know better.