Calmag deficiency under Cree 3590 LED (1100) PPFD)

Hey Guys!

Could this possibly be a Calmag Deficiency?
Temps range from 22 to 26 Celcius and humidity is at 55%. I am growing on Soio with Drippers. Currently Day 29 of flower.
I am already using Calmag but probably not enough?

Strange thing is brownish spots seem to appear only when two leafs overlap closely !!?

What is your nutrient make-up ?

Nutrient Make-Up @ the moment is around 900 ppm Terra Flores + 250 ppm Calmag based on low EC Water. PH ranges from 6.2 to 6.5.

Problem appears more on lower and older Leafs.
Stems tend to be red also.

Seems a little high for your feed ppm's. I only Charge my RO water to 100 ppm of cal-mag before mixing my nutrients in. I only run around 600 ppm at max.
I'd cut back on the nute's and replace some of the cal-mag with some mag product alone.

Ok, only a guess but lets go. If two leaves are sort of overlapping there would generally be higher humidity around there. Less airflow, larger concentration of stomata per volume yadayada.
Higher humidity means VPD is lower which can endup closing the stomata, which makes sure that those leaves arent transpiring enough, which means not enough water and nutes are being brought to that leaf. Your temps are in the lower range of whats recomended for led, try raising it. 25-28, or even up to 30C is what ive seen recomended around here. Or lower Rh but maybe less desirable. Try making changes slowly and check how leaves and new growth react.

Its not allways about what you put into your plants, sometimes its about making sure your environment lets the plant uptake what you feed it efficiently.

peregrines said:

Could this possibly be a Calmag Deficiency?

Click to expand...

imo, no.

more like old growth or maybe a slight phosphorous deficiency. Could also be caused by large pH changes.

Okay, I cant let this go.
Call this nitpicky if you must ( it is), but I see it all the time, and find it super irritating.
CALMAG is a nutrient supplement, with CALCIUM and MAGNESIUM as ingredients. (sometimes nitrogen as well)
Plants can be Ca deficient, or Mg deficient, and CALMAG does supply the elements to prevent either one of these ….
A CALMAG deficiency does not exist.