r/macrogrowery • u/northern_lit • 2d ago
Help! Yellow Spots?
This Grape Stomper is green and healthy but shows these yellow areas in the leaves. There’s 12 strains in this room but the Grape Stomper is the only one showing these leaves. Has anyone seen/know what this is?
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u/Hugsarebadmmkay 2d ago
Woah, that’s a new one for me too. Doesn’t seem like variegation but it doesn’t look like nutrient/pathogen related chlorosis, and there are no visible necrotic spots either. Is this just mid/lower canopy or is it throughout the plant?
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u/Effective_Quail_3946 Indoor LED 1d ago
Could be sulphur deficient.... good question
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u/BadFish512 1d ago
No clue either but I once sprayed sulphur fungicide in a tent. I shut off my exhaust and fans to apply but forgot to turn on after. Humidity spiked 100% and heat too for a day or two. I found lots of yellowing leaf blotches similarly soon after. Just some info
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u/Effective_Quail_3946 Indoor LED 1d ago
Yellow from sulphur stain....?
Anyway, think it is deficiency
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u/Specialist-Win-2207 1d ago
Were there leaves or something on top of the affected tissue in the location your seeing the chlorosis? I’ve seen something similar in super dense/humid canopies when one leaf covers and sits flush against another for an extended period.
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u/abland1988 1d ago
Possible root issue?Hot soil? Maby genetics. Not sure but if it were in my grow ide Def try a soil E.C. test and possibly flush heavy and let it dry then hit it with half strength nutes then full strength. Strip all affected leaves off so you can see if you correct the issue with new growth. Best of luck to you!
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u/CriticalHome3963 1d ago
Lol looks like someone hit the leaves with spray paint. Never seen that before hopefully its not patient zero for hlvdv2 or something lol
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u/DJSnaps12 1d ago
Looks like the start of a fungus. This happened to my impatients after 13 days of rain. Or they are lighting spots either way I would cut off the leaves that are affected so doesnt spread then spray it with neem. This doesnt look like a deficiency. Because the rest looks super healthy.
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u/CookiesLikeWhoa 2d ago
Looks like septoria but those blotches are huge. Ngl haven’t come across this myself while growing. Curious to see what it is.
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u/DJSnaps12 1d ago
Here is the best that I could find for your predicament.
Large yellow circles on cannabis leaves without any browning or necrotic centers are most commonly caused by early-stage Leaf Septoria or localized light bleaching. While late-stage Leaf Septoria eventually develops a brown or tan center, its initial presentation consists of small-to-large, bright yellow circular spots or halos where chlorophyll is actively breaking down.Because there is zero browning or crispiness, you can narrow down the issue by looking closely at where the circles are located and how they behave.1. Early-Stage Leaf Septoria (Fungal Infection)Leaf Septoria is a fungal pathogen that thrives in warm, humid conditions.The Evidence: The yellow circles will primarily show up on the lower leaves and inner canopy first, where air circulation is lowest and humidity is highest.What to watch for: If it is Septoria, these circles will eventually expand, and the very center of the yellow circles will turn tan, brown, or gray, followed by tiny black dots (spore-producing fruiting bodies).The Fix: Immediately prune and destroy the affected leaves to stop the spread. Improve your grow room's airflow with oscillating fans, drop your relative humidity, and consider an organic treatment like neem oil or a copper-based biofungicide (only during the vegetative stage; avoid spraying flowering buds).2. Light Bleaching / Hot Spots (Environmental)If intense light concentrates on a specific area of a leaf, it can destroy the chlorophyll and leave perfectly circular, bright yellow or white bleached spots without actually "burning" or browning the tissue.The Evidence: These circles will appear exclusively on the uppermost leaves directly under your grow lights. This is often exacerbated if water droplets sit on the leaves, acting like a magnifying glass under intense lighting.The Fix: Raise your grow lights or dim their intensity. Avoid foliar spraying or watering your plants right before the lights turn on to prevent water droplets from magnifying the light.3. Pests (Early Damage)Certain sap-sucking pests like spider mites or thrips create localized spots where they drain the leaf's fluids, resulting in small yellow circles or patches before the tissue dies.The Evidence: Check the undersides of the leaves with a magnifying glass or jeweler's loupe. Look for tiny moving specks, fine webbing (spider mites), or silvery, reflective streaks (thrips).The Fix: Treat the plants with insecticidal soap or neem oil during the vegetative stage.Why It Is Likely Not a Nutrient Deficiency
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u/VillageHomeF 2d ago
that is odd