Is this LED light burn?

Using a Viparspectra 600 full spectrum LED light, my second week flowering plant is turning yellow. I have read that yellowing leaves is common during flowering, but four other plants all turned hermaphrodite and I’m looking for stressors. The light is 24 inches above the plant. Does this look normal or stressed?

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24" sounds reasonable for flower. I have my 900’s at 18".

Can you list more info in a support ticket?

COPY/PASTE: This “Support Ticket” into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA

Strain; Type, Bag seed, or NA

Soil in pots, Hydroponic, or Coco?

System type?

PH of runoff or solution in reservoir?

What is strength of nutrient mix? EC, or TDS

Indoor or Outdoor

Light system, size?

Temps; Day, Night

Humidity; Day, Night

Ventilation system; Yes, No, Size

AC, Humidifier, De-humidifier,

Co2; Yes, No

Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you

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Strain: Bought from dispensary, unknown type, looks indica
6 inch rock wool cube
PH of water kept at 6.5-6.8
What is strength of nutrient mix? Only rainwater, no TDS meter
Indoor small bathroom
Light system: “600 watt (effective) full spectrum” LED. 256 watts actual at 18-24 inches.
Temps; Day: 76°F, Night: 68°F, 2-step thermostat controlled space heater
Humidity; Day, Night 45% to 60%
Ventilation system; None
Co2: No

After learning that plants in soil should get a half dose of “Elite” nutrients, this plant, too, got a half dose. It only now occurs to me that perhaps the yellow is due to insufficient nutes.

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If I’m not mistaking rockwool is considered non-soil and PH should be lower, like 5.8. Let someone else chime in, though.

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I’m with @Matthew420 here. Can you clarify your grow medium? @ProctorPot

Right on @Matthew420, the PH in rock wool should be around 5.8 for the sweet spot, it’s clearly a PH issue @ProctorPot and you should give them some nutrients, they also clearly showing sign of under feeding.

~Al :v: :innocent:

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what brand of soil did you put your rock wool cube in?

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The plant is in rock wool, and not in soil. I had four other plants in soil that are getting the same nute mix, so they all got readjusted. I can nute the rock wool separately if that’s the problem.

So the pH should be 5.8 and the nute mix should not be reduced like it is for soil? This is my first grow, I know nothing.

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Yes @ProctorPot and go gradualy from half strength to three quarter to full strength with the dilution of your nutrients and just follow the chart

~Al :v: :innocent:


Since it’s not a soil mix, a cal mag supplement will be required and a silica one, too…micro nutrients available in a soil mix but missing in yours.


One of the easiest ways to know if you have light burn or not, and LED’s light burn is actually not much different than HID/HPS/MH light burn, is that the parts of the plant closest to the light source have the most damage. And in this case, it is clearly not the top of the plants. Also, in general, especially with LEDs, when it is only “light” or “photo” burn, and not heat burn, the plant parts “bleach out” – this is known as photoinhibition, a break down of the chlorophyll, and so they actually lighten in color, to even becoming almost totally white.

And so I’d have to say this is not LIGHT burn at all.

And so yes, it is a pH issue as others above confirmed.



Good to see you around @MacGyverStoner, Hi :grinning::v:

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I don’t want to hijack this person’s thread with a lot of small talk, but thanks, and I’ve been busy doing some detailed help in the other forum, Bergman’s Lab.

See everyone around,



I have returned to full strength nutes with a pH of 5.8 in my rock wool. The leaves are not any darker, and may still be getting lighter. Is there no chance this is just a natural result of blooming?


It looks like calmag deficiency.