As a nube, I'm not 100% sure that flowering has begun, but noticed an increased amount of new growth where the flowers should start to appear. So, on day 46, I began to transition over to the Flowering Stage.
LIGHT CYCLE: Switched from 18/6 to 12/12. But, to minimize interruptions to the dark periods, I adjusted the start time from 5am-10pm (Ugh, just realized that's only 17, not 18 hours). The new schedule is now 6am to 6pm.
LIGHT: For this week, to encourage both growth and flowering, I've switched on the Red LEDs in combination with the Blue LEDs. However, I raised the light up about 4 inches to try and avoid light burn.
WATER/NUTRIENTS: I'm still watering with the remaining NPK mixture, but only about a cup per day.