Hey man, after a period of 12/12, sometimes a plant will have a rough time returning to the veg cycle. If you go with a 24/7 for at least long enough to see one nodes worth of new veg growth, you may save some time due to continued flowering or slow recovery to the veg cycle.
Whack the nutes to a high nite mix and watch for any sign of burn. If you get it, in dirt, flush and reduce the nites. In Hydro, alter your mix to bring the nites down and flush for a couple of hours. I gotta tell you man, if you're still using dirt, you might want to check out doin the hydro. Growing in dirt is like slapping mud on a cut when you've got a bottle of antibios layin next to you. It'll work like it always has, but you're missing out on some serious improvments.
Why'd you decide to return to the veg cycle?