Brown spots on lower leaves. What is it?

Hi. I’m having some issues with my plant. It started showing these spots a week and half ago. It started on the lower leaves and every 4 days or so it moves up to the next node. Last 2 feedings I gave her micro grow and bloom from advanced nutrients (ph perfect line) at a ph of 6.8. Last 2 feedings I gave it 2ml/L of each bottle. With my most recent feed I also added 0.8ml/L of calmag as I read that it might be a calmag def. So far it stopped but want to double check this with some of you. Those spots start kind of a silvery color. It looks almost like some sort of liquid hit the leaves but I didn’t hit the leaves when watering/feeding. I added a photo when they first started showing up. She is an autoflower currently flowering. It has a few pistils on the top half of the plant and its outdoors. I also added some photos of the full plant. If you need anymore information please let me know. Thanks

To start with she is pot bound the smaller one will be soon, looks like magnesium deficiency. Lower the PH a bit closer to 6.3.

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does it look root bound?

Looks like it to me . Is that root ball extremely firm?

not really. I slightly poked it with my finger and it wasn’t firm at all

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How about a bit more info:

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 (photo or auto)
-Age of plant
-Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF
-Vessels: Type and capacity of container (fabric, plastic, etc)
-PH and TDS of Water, Solution, runoff (if Applicable)
-PPM/TDS or EC of nutrient solution if applicable
-Method used to measure PH and TDS
-Indoor or Outdoor if indoor, size of grow space
-Light system List brand and wattage/spectrum
-Actual wattage draw of lights
-Current Light Schedule
-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 in white light of any issues you may have to allow the community to assist you.

What strain, Seed bank, or bag seed (photo or auto): Gorilla Zkittlez auto from Barney’s farm
-Age of plant: 37 days including germination. 34 days since it came out of “soil”
-Method: coco/peat/perlite mix
-Vessels: Type and capacity of container: Plastic pot 2.9litres
-PH and TDS of Water, Solution, runoff: Ph of water: 6.8. Runoff ph: 5.5. EC of nutrient solution: 1.6 runoff:1.4 EC
-PPM/TDS or EC of nutrient solution: 1.6 EC
-Method used to measure PH and TDS. Ph meter and EC meter
-Indoor or Outdoor:outdoor
-Current Light Schedule: 5 hours of direct sunlight. I only get 5 hours in the afternoon in my balcony.
-Temps; Day: 30-34 degrees celsius Night: 26-29 degrees celsius
-Humidity; Day, Night 55-60 day and night
-Ventilation system; N/A
-AC, Humidifier, De-humidifier: N/A
-Co2; Yes, No: N/A

I think I’d first bump my nutrient solution up to 2.0 EC and PH around 6.0 due to the presence of peat along with the coco. Definitely add cal mag as it appears to be a def. Remember to look to new growth as those leaves will not recover.

More light would be beneficial as well.

I added 0.8ml/L of of calmag in my most recent feed. It stopped for now. Hopefully it stays that way. When you said to increase my ph to 6, did you mean the runoff ph? because im watering and feeding at around 6.8-6.9ph because of the acidic runoff. Even when I managed to get runoff to around 6.1, after a couple of days it dropped back to 5.5.

I actually just remebered when the issue started. Before I started seeing these spots, I had heavily flushed the plant because of too low runoff ph. As a result the medium was completely depleted from nutrients. right after the flush, I gave it a small dose of nutrients and the runoff came back at 0.13 EC and I left it. The next day, it developed these spots on the node below the one I posted. Then after 3 days, I fed it again with a higher dose and EC runoff came back to 0.77. It was okay the next day and then another day went by and it developed the spots on the node that i posted. most recent feeding I gave it the same dose as before but I added some calmag as well and so far, 2 days later and no new spots. I think I might be underfeeding the plant as you suggested

Your runoff PH is fine for the medium you are using. As plant develops flower the PH is likely to drop more as some organic material in the medium (roots) will start to die off and render medium acidic.

Plant will probably benefit from a higher dose of cal mag and hold your EC at around 2.0 (1,000 ppm). I would run cal mag at the upper end of the recommended dosage.

FYI coco tends to sequester calcium and magnesium so cal mag is wise to use with it.

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Thanks. I will definitely give that a go and post an update in a few days. What ph should I water/feed with. I usually both water and feed at around 6.8-6.9 ph. should I lower that because of the peat and coco?

I added a photo of the mix I use as well if it helps

Typically you transplant when the first set of leaves tips reach the edge of the pot growmie, keep pulling it out the pot like that to check for rootbound will just cause more stress