LED Burn or Nute Problem

[hunter548]

Been having this yellowing issue for quite a while, although it seems to be worse lately. I'm a long time inside/outside grower, but 1st 2.5x2.5x5ft tent grow under an LED light (Mars Hydro 1000). I'm seven weeks into flower (Gelato) and been using Fox Farms Big Bloom and Tiger Bloom. NPK and PH (6.0) checked out Ok. LED is about 18" from the top of the plants.

I measured the PPFD at 1100-1300 (set it there per one "expert" opinion). I dropped it to 750 (per another "expert" opinion) to see how it goes, but I wondered what you folks think.

 

[Roy Growin]

Been having this yellowing issue for quite a while, although it seems to be worse lately. I'm a long time inside/outside grower, but 1st 2.5x2.5x5ft tent grow under an LED light (Mars Hydro 1000). I'm seven weeks into flower (Gelato) and been using Fox Farms Big Bloom and Tiger Bloom. NPK and PH (6.0) checked out Ok. LED is about 18" from the top of the plants.

I measured the PPFD at 1100-1300 (set it there per one "expert" opinion). I dropped it to 750 (per another "expert" opinion) to see how it goes, but I wondered what you folks think.

They look really chunky, so they're probably burning up nutes
I'm not really a big fan off PPFD measurements, EC and all that jazz - a TS1000 @ 75% is plenty
In fact, I dim it to 30% overnight and only turn it up 12pm - 6pm on a 10am-10pm cycle
My solution when plants are looking like that is CaMg/PK followed by BioBizz 1ml Grow, 3ml Bloom with Algae extract
Greens them up overnight and they stay that way

 

[Sueet]

I suspect your plant is missing the nutes that come in the third bottle in the Fox Farms 'trio' that you are using only two parts of.

 

[hunter548]

Here's two others Both grab bag Mexican Haze. One showing the yellowing the other just turned purple. Turns out Trichomes on all three Haze are 90% milky 10% amber and the Gelato 50% milky 50% amber so it seems they're ready to harvest anyway after 7 weeks flower, 12 weeks veg (manifolding technique dragged the veg cycle way out). I had expected the buds to be significantly larger, but they are what they are. Just want to apply what I learn to my next grow.

 

[hunter548]

They look really chunky, so they're probably burning up nutes
I'm not really a big fan off PPFD measurements, EC and all that jazz - a TS1000 @ 75% is plenty
In fact, I dim it to 30% overnight and only turn it up 12pm - 6pm on a 10am-10pm cycle
My solution when plants are looking like that is CaMg/PK followed by BioBizz 1ml Grow, 3ml Bloom with Algae extract
Greens them up overnight and they stay that way

Thanks for the advice. Was thinking about the CaMg route, but noticed the top leaves are the worst and those underneath the yellow leaves were mostly green,

 

[FelipeBlu]

@Growings and @Sueet are on point - they were all in need of more feed. These strains at least, seem to want more fertilizer in mid-flower - in particular - N, K, and Mg.