Do you have pics? you can put them in your album if you don't have enough posts. Sounds like your plants are becoming nitrogen defiecent, which is normal in flowering, leave then on for a source of food until they fall off at the slitest tug. you can give a balanced 1/2 strength nutes, but they'll be fine as it's the natural process. next time keep N going 2-3 weeks into flower as they need it for the "stretch" period.