is 1 sunlite 42w 120v Fluorescent lightbulb enough light for my 3 plants they are all about 4 weeks old i bought them about 3 days ago i had them in light on 24 hours a day 12in above plants till an hour ago i turned them off because my leaves are turning yellow and crispy im worried that the will die any tips or advise please!!! has to be someone out there