LED's, is full power needed?

[GreenVision]

Hi all, a little background info, I crossed some plants a few years back and during a large pheno hunt found a plant I absolutely love and I've been using cuts ever since. Its been a few years now and I had what I suspected were vigour issues possibly down to me taking cuts from cuts or just me... 

 

 

Fast forward to my current crop and they're looking the best they have in quite a while, I'm all but 3 weeks into bloom now and they've stopped the stretch. I think the change in soil and lights has helped them come back to life.

 

I now have 6 Lumatek ATS 300w pro LED's above a SCROG, and the LED's are currently set at 75% and about 35CM above the canopy.

 

My question.. Do I leave them at the 75% or should I raise them up a little and go full metal jacket? Would I loose any yield to only having them at 75% over the 100%?

 

Kinda stuck on this one, on the one hand I think yield will drop slightly not having them up full as there will be less light, but on the other hand if I turn them up and they freak out on me I could end up stressing the shit out of them and not only lengthen my bloom phase but possibly loose yield to stress and over lighting.

 

The LED's are pretty forgiving being a smaller unit, I think even at 100% 40cm above canopy they don't go above the recommended 1000 ppfd at all. The plants however are not so forgiving, since the off this cut has a clear temperament to light schedule and temps, not so much light intensity but when the light go out its one of those that just goes all down and instantly goes to sleep. 

 

So I suppose it does come down to yield. Obviously I want to get the max I can so will the dimming down to 75% affect the yield at all?

 

Cheers.

[Military Grade]

Depends on the lights, too high of hot spots on your par map and they can hinder the yield in that area than turning the lights down.

 

Many Growers on here don't run their lights at full power.

[GreenVision]

Well the par map on Lumateks site says that at 40cm they are really nice and uniform, plus no areas higher than 1000, which I think the max I should be at without more equipment etc. 

 

But at 75% those numbers will obviously be down so Im thinking yield should follow?

 

[stu914]

I run my 550w scope leds at 400w giving around 850 - 900 umols overall.

Returning between 1gpw and 1.5gpw, strain dependent, Any higher and the

upper leaves canoe. Sounds like you're more or less in the sweet spot GV.

ATB