Hello, and

to the AFN forums :smoking:
I have a Meizhi 300w, but it doesn't have the veg & bloom switches, however my Mars Hydro 48 Reflector does, and I have used the veg light for the first couple of weeks, then switched to bloom around week 3, but using both from the beginning is also fine apparently, from what I have read.
Someone will correct me if I'm wrong here, but as far as I have read, the veg light can be used solely for the first couple of weeks, without the need for the bloom light, however I have also seen posts where people run the lights with both switches on from start to finish.
It will not hurt the plants (I don't think at least) to use just the veg light for the first couple of weeks (without the bloom light on), as the plants are not in bloom yet, and would not be making efficient use of that light spectrum.
In relation to the best technique, I would just keep it simple, ensuring the lights are around the correct distance / height from the plants, and you have adequate ventilation and airflow.
What autos are you thinking about trying?