Whats the best height for lighting on established plants?

I have a plant under a screen thats 22inches or 60 something cm from the leds, they are cree cxb3070's, 4 of them about 12 inches apart.
Ive noticed some yellowing on some leaves but that could be from putting my plant in the ceiling space due to an inspection on my rental.
I lowered the light to what measurements i said earlier lowered it about 6 cm to 22 inches above the screen. its still in veg untill my plant reaches the edge of the screen.

Any advice appreciated.

I use cobs as well, it kinda depends on the plant but In general I start flower around 18 inches above the canopy and move down to between 12-16 slowly. It’s pretty hard to burn your plant with cobs. Is the yellowing on the very top leaves?

In veg 18-24

Grow So High said:

I use cobs as well, it kinda depends on the plant but In general I start flower around 18 inches above the canopy and move down to between 12-16 slowly. It’s pretty hard to burn your plant with cobs. Is the yellowing on the very top leaves?

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thanks for the quick reply its yellowing on the lower leaves and two top leaves where i cut off the tip for clones