Yellow Spots on One Leaf

Hi All,

Anyone have any thoughts on what has caused these yellow spots? They seemed to appear overnight and only affect ‘one’ upper most leaf on one of my 3 plants.

The plant is about 5 weeks old and 12" tall. I am leaning towards a pest or fungus because it is isolated at this point. Any additional info I can provide to the community let me know.

Look forward to your help!


Full plant pic, and some data would be helpful

Ph tds rh temp

1 Like


A support ticket will help us help you. Can you please fill out a support ticket? Please include what type of water you are using.

COPY/PASTE the below list 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; Or post

NA (non-applicable)

• What strain, Seed bank, or bag seed

• Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF

Soil brand and type

• Vessels: Pots, Grow beds, Buckets, Troths

• PH of Water, Solution, runoff (if Applicable)

• PPM/TDS or EC of nutrient solution if applicable

• Indoor or Outdoor

• Light system

• Temps; Day, Night

• Humidity; Day, Night

• Ventilation system; Yes, No, Size

• AC, Humidifier, De-humidifier,

• Co2; Yes, No

If growing Hydro some additional questions:

-DWC? RDWC? Autopots? Ebb and Flow? Other?
-Distance of liquid below net pot (DWC)
-Temperature of reservoir
-TDS of nutrient solution
-Amount of air to solution

Always try to upload a clear picture of any issues you may have to allow the community to assist you. Pictures taken under natural or white lighting are by far the best.

Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner.

1 Like


Requested info and photos of the entire plant… I guess i mixed my soil too hot and all three plants are clawing from the excess nitrogen, but not seeing any burning on the tips anywhere, hoping they will just push through as the soil depletes some over time.

• What strain: White Widow from ILGM

• Method: Organic soil, FF Ocean Forest amended with Dolomite lime, Garden Tone, Worm Castings and Mykos applied to roots during transplant.

• Vessels: 3 Gallon Fabric Pots

• PH of Water, Solution PH: 7.6, EC: .331 — Runoff PH: 5.9, EC: 4.995 (soil is really hot) (other two plants PH runoff is about 6.7, so with my lime buffer I don’t know if i trust my last measurement, other two plants measured 6.7 PH runoff)

• PPM/TDS or EC of nutrient solution No Nutrients yet

Indoor or Outdoor

• Light system: (3) Growstar Full Spectrum LED, 115 watt actual current draw each, 20" Above canopy, running 2 at any one time.

• Temps; Day- 70 deg. F, Night- 70 deg. F.

• Humidity; Day- 62-65% RH, Night- 62-65% RH

• Ventilation system; Separate intake and exhaust fans providing 5 air changes per minute roughly

• AC- 8k btu portable (way oversized hence poor humidity control), Humidifier= yes, De-humidifier= no,

• Co2; Yes, No

If growing Hydro some additional questions: NA

Humidity is not all that high, but I still suspect mold. Everything else other than pH looks pretty reasonable. Try spraying a dilute solution of hydrogen peroxide on the leaf and see how it goes. I use 5:1 water:peroxide. If that doesn’t address it, we’ll have to look at other things. The leaf will have a hard time healing, but if it is mold, the peroxide will kill it instantly and prevent further damage.

It best to apply any sprays just before lights out. It slows evaporation and prevents burning of the leaves.

You’re going to want to increase runoff pH to as close to 6.5 as you can get it.

You will want a lower humidity when you get to flowering.

Thanks for the fast response… I will do as you suggest and spray with hydrogen peroxide and keep a close eye on it…

This is my third grow and the last two were far from issue free, this one does seem better so far.

My next watering i will verify the PH of the runoff, it is a lil hard for me to believe it is that low with all the lime I mixed in the soil. If it is really that low how can i raise it? Last grow i fought low PH the entire grow, added water and hydrated lime mixed to PH 13 a couple of times, flushed a couple of times… couldn’t get the runoff above 6 with any of my efforts.

I am working on a dedicated dehumidification mode for my AC, hopefully I can get it dropped to under 50% if i want to.


Input ph should match output ph. There’s an issue if your input ph @ 7.5…

Curling of leaves shows that as well as the spotting from deficiency from the ph range.

I’d recommend you fix ph for medium your in and try adding an amino acid to you additives if this continues.

Plants will still take in nutrients even out of ph range with this supplement


Thanks for the reply. I stopped adjusting my input PH after reading it wasn’t necessary or even advisable with the mycorrhizae because of the additional acids. But you know how it is there is so much information it gets really overwhelming for someone like me that is new to it all. Before my next watering I think I will do a quick slurry test and dial down my input to match that. Then see what the run off is.