I'm currently in the 3rd week of veg using an 18/6 lighting schedule and I'm nowhere near being ready to change to 12/12 yet. BUT.... I just realized that in another few days I will not be here to turn the lights off after their being on for the 18 hours. (a timer won't work with my configuration) I need to start turning the lights off 2 hours earlier than I do now. If I make the change all at once, will that stress my plants? Should I spread the change out into equal times over the next few days? Thanks.