Support ticket, mustard yellow spots

Maybe I’m worrying over nothing. But I don’t want them to start having problems just as they are starting to flower.

Support ticket:

  • What strain:
    • White widow CBD Auto,
    • Kush CBD Auto,
    • Critical Mass CBD,
    • Gold Leaf photo
  • Seed bank: ILGM
  • Method: 70% coco, 30% perlite
  • Vessels: knockoff air Pots
  • Water pH in: 7.1
  • Water pH out: 7.2
  • pH soil while watering: 6.0 - 6.5
  • Nutrients: full Jacks 1-2-3
  • PPM in: ≈1600
  • PPM out: ≈1600
  • Indoor
  • Light system: MIEEMCLUX C2000 LED Grow Light with Wide Footprint 4x4ft set at 40 - 60 DLI depending on where I measure the canopy
  • Temps: 70 - 78F
  • Humidity: measuring, rest of house is ≈45 rh
  • Ventilation in: VIVOSUN 4 Inch 195 CFM blowing ≈ 66F air in constantly
  • Circulation: two pole mounted fans
  • Ventilation out: Vanleno 4inch Carbon Filter
  • Heater: 150W Ceramic Heat Emitter Reptile Heat Lamp controlled by an inkbird set at 76F
  • AC, Humidifier, De-humidifier: No
  • Co2: No

All of the autos are in pre-flower but they have had this in vege. All of the autos all have a couple leaves with this mustard yellow spot. It isn’t many leaves, just 1 to 3. They are also older leaves, 5th - 7th cola. On all but one leaf, the discoloration is where the leaf has been damaged by my while LSTing the plants. What concerned me today is I noticed the larger spots on the undamaged leaf.

Auto pics:

While I’m here, from time to time I notice wet spots on the Gold Leaf photo (still in vege), usually where two leaves are touching, one on the other. Today I was able to get a good-ish picture of it. Basically, it looks like someone spit on it, water with a few bubbles. Maybe it isn’t getting enough air movement. I adjusted both pole mounted fans tonight to improve air flow.

Gold Lead pics:

Thank you.

Also, I’m running my lights 20/4.

RH is about 45 - 48%.

And a group photo:

Kinda looks like it may be damage from water on leafs and light burning them through the water…
Mine also alot of times get moisture build up where leafs stack up if not directly hit by a fan to kinda move them around a little. It can be from high humidity or simply very active stigmata transpiring.
It’s normal but expect to see damage there to if ya can’t get better air flow to places you see it building up or leafs laying on each other…

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Did you say you was watering with ph of 7.1 and getting 7.2ph reading from run off?

I calibrated my meter tonight and took measurements just to be sure. I wouldn’t trust it’s accuracy to be less than +/- 0.1.

The in soil pH reading was a while ago. I’d have to take a new one tomorrow when irrigate again.

The closest picture I’m seeing is heat stress from ILGM’s website:

My wife also suggested that it’s either condensation or fertigate got on the leaves and then got burned by the light. I started off with above ground drippers and eventually switched to subsurface drippers.

If it’s fertigate on the leaves, that explains why it’s only on old, lower leaves.

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I peaked in again before bed and saw some more spots higher up the plants

Could also be bugs muchin on your leaves, check the undersides for mites

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Looks like nutrient/water splash on the older leaves. Transpiration will increase as they get older and leaves laying on each other during the veg will create the water droplets or spit as you called it and can be burn/scar the leaves from lighting :love_you_gesture:


These are pictures under a couple damaged leaves.

The only bug I’ve seen in my tent was a solitary gnat, the first day I moved everything in and I killed it.

My list of suspects from similar pics is: nutrient splash, light stress/burn from transpiration, and pH stress without severe iron deficiency.


Okay, this one has gotten worse from yesterday. I definitely need to figure it out. I guess I’ll start with adjusting pH down.

This is yesterday vs today.

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I am a little confused about the ph info given. You are growing in coco. All solutions should be ph’d to 5.8 to 6.1. I usually use straight 5.8.

What size is the tent?
I went to Mieemclux site. I did not see a PPFD map. I can tell you it is only a 200 watt light. It is directly comparable to spider farmer SF-2000 except SF is designed to cover a 2x4 space and uses good Samsung diodes.
These are its DLI calculations based on avg PPFD taken from published maps


I’m sticking with pH stress not now. Checking pH every step along the way today as I mixed new nutrients. (I also mixed 3/4ths strength Jacks today just in case I was stressing them with too much nitrogen.)

Tap water = 7.8
Water + nutes = 6.8

The water + nutes must have been drifting up to 7.1-7.2 over the course of two or three days while the 5 gallon bucket gets used and stressing the plants now that they are in bloom.

Today I adjusted the pH down to 6. I’ll see how it looks after it irrigating again in 2 hours.

My tap has similar pH. Jack’s will drift up over time. Because of this I would occasionally adjust down below 5.8. If you use 5.8 and feed enough to produce 25% or more runoff, it will help get things back where it needs to be.

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To summarize why I wasn’t testing & adjusting the pH before it’s, “lazy.” Too much crap going on & I was too lazy to calibrate the meter.

The tent is a 4x3 sectioned into a 3x3 and 1x3. I have the plants on the big side and my tools, chemicals, & reservoir in the small side.

In retrospect, I can see how a 3x3 is too small 4 photos unless I SOG. I think I’ll be okay with 3 autos and a photo in vege if I stick with LSTing everything. Managing the canopy height has become more challenging with the autos stretching in flower.

I like the light but it is under powered - which is why I don’t think I’m light stressing them. I think the only reason I’m getting away with using it is because I’m running it 20/4.

Unfortunately, a light upgrade will have to wait for my March bonus. I haven’t decided if it would be better to have two 200W LEDs in the tent that I can run from 50% to 100% or have a 200W for small plants and a 400W for larger plants.

Thank you for the help.

Yes it is. It will be a tough ask for it to flower a 3x3 space. It will do fine for veg. You will need to go to 12 hour schedule for the photo to flower. Otherwise it will just keep growing.

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The compromise I made is that I won’t flip it to 12/12 until after I harvest the autos. That way the photo is in there by itself during its bloom.

What will be its total veg time? The longest I have gone is 70 days and I mainlined with significant LST.
Also, Gold leaf is described as a tall strain

Most likely PH related as you’ve mentioned. I use Jacks as well and will have some plants that need extra calcium and magnesium. The rust spots if not splash burn are typically Calcium deficiency and accompanied by magnesium. Coco PH range is 5.8-6.2 for my personal preference, this range allows optimum nutrient uptake for the different nutrient PH ranges. When I see this or suspect this deficiency I increase the epson salt and cal nitrate (calcium and magnesium) :love_you_gesture:

After two irrigations and an overnight rest, nothing looks better or worse. If that stays true through noon, I’ll take it as a win. I’ll also check the reservoir pH at that time to see if it has drifted again.

@beardless, it will be 3 - 4 months, probably on the longer side.

Checked the reservoir pH, after not quite 24 hours and it’s drifted up from 6 to 6.25. I’ll mix new nutes tonight at pH 5.8.

Nothing looks significantly better or worse than yesterday. The Critical Mass might look more verdant and less dark lime today.