@RndmGrwr, For seedlings I've been doing 30'' at 50% till week one, then 75%. Week 2 up it to 100%. Week 2-3 I drop down to 22'' for veg. That's technically within the recommended for these lamps. When it comes to flower however, I'm like most growers and try to push the limits - get the most I can out of them. I saw some burn my first grow around 12'' and 14'' but I still had some excess chlorine/chloramines to take care of in my tap water (week 10).
This grow I'm starting flower out at 15'' - I let them grow into it these last two weeks with no issues so far, well see it how goes! (You'll see a lot of people trying to push 6-12'' for flower, and sometimes you can get away with it, light/genetics/care depending. Best to start high and work your way down). You have one light / four plants, so keep your 4x3 spread in mind - too close and the outer edge of each plant will miss out, so I would stay around 18-20'' till the chop. Hope this helps growmie - good luck!
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