I had it at 6in but noticed yellowing n thought it might b light so I went upYou're going to have to play with it. I'd try 6 inches/15 centimeters and see if it causes light burn (I doubt it would). You may be able to lower it more than that.
600 mh for veg thanks bro iwill look up chartHow many watts is your bulb? Is it a metal halide or HPS? I tried to send a link, but the posting is being held up for moderator approval. Google HID distance charts…..it will roughly tell you how far away to place your grow light. You can also use a lux meter on your phone to determine ideal lighting. Seedlings don’t want any more than 7,000 lux.
Thanks bro I will try it out and flip @ 20 inLooks like your topping them. Sure other thoughts but overall look healthy. To me that matters most. Size is relative. If they are not autos, you can veg to the size you want then flip to flower. I go 8 weeks from seed to flip to flower on avg. Sure I could get it down to fewer weeks of seedling/veg but not yet.
Me personally I go to about 20in to 24 inches in veg. I don't want anything larger than that when I flip to flower. With topping that is plenty to get at the very very very least 4oz per plant.