hey JN welcome you didn't say if they were inside or out ,since you said you were covering them and not turning out the lights I am going to assume you are outside . Outside I have some plants that are starting to bloom right now, the amount of sunlight is less than 14 hours so if you are outside you can stop covering them when the sunlight gets to 12 hours, I'm not sure if you stopped covering them if they would go back to veg with the sun at 14 hours but its a huge risk and you do absolutely need 12 hours of uninterrupted darkness to bloom