Necrotic Spotting on Lower Fan Leaves

Troubleshooting
1

Hi All,

I haven’t reached out for help in a while but I need some advice on this one. I have brown spotting on my lower fan leaves.

Here is info on my grow:

• What strain: Bubble Gum from ILGM

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

• Vessels: 3 Gallon Fabric Pots

• PH of Water, Around 7ish

• PPM/TDS or EC of nutrient solution NA

• Indoor or Outdoor

• Light system: (3) Growstar Full Spectrum LED, 115 watt actual current draw each, 14" Above canopy 22-29K LUX— estimated PAR 800-1050 ppfd/umol/s/m2., DLI about 30 mol/m2/day

• Temps; Day- 75 deg. F , Night- 75 deg. F.

• Humidity; Day- 55% RH , Night- 55% RH

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

• AC- 8k btu portable , Humidifier= yes, De-humidifier= YES,

• Co2; Yes, No

If growing Hydro some additional questions: NA

This plant is about 7 days in from the start of flowering (pistils). Overall it has a nice green appearance. The symptoms I am noticing are twofold:

Brown Spots on lowest fan leaves

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And noticeably thin leaves at the very top of the plant (the purple tint is from the LEDs, the leaves are actually nice and green):

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I did a top dress about 2 weeks ago with:

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I did a slurry test about 5 days ago, here are the results:

PH 6.67
EC 3.03
PPM (.5) 1520

Last watering I did was tap water and a little bit of molasses. I am not good at troubleshooting leaves, but I am leaning towards an excess of Potassium which is causing some other lockout issues.

I know from researching this is rare and I might be looking for some exotic issue. Hopefully you guys can steer me in the right direction with a more common problem.

I appreciate your help!
Axis

2 Likes
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was the fan leaf at the bottom?

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Yes, the very bottom.

4

My first thought. Whenever I see spots bigger then calcium spots, on a plant into flower? Its normally Potassium related or pH related.

Seeing this worries me as well. Ur slurry u knew was 6.7. The pH of solutions was around… how certain are you of this value?

4 Likes
5

does it sometimes happen that botton growth sacrifices its lower leaves to focus more energy into the flowering buds? or am I just retarded?

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To be honest, I stopped checking the input PH as my slurry tests have showed mid to upper 6’s… hold on a second and i will test my water…

1 Like
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No you are not retarded at all, and it could be just that. My other two plants aren’t showing these signs (different breeds)

PH is 7.7. I set my tap water out for a few days to help dechlorinate it. Last grow I always checked input and output and recorded the results. Runoff EC was useless but the PH was always in the 6-7 range no matter what the input PH was.

1 Like
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I put mine in the tent and let sit to do the same. my tap water sucks

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PH is 7.7. I set my tap water out for a few days to help dechlorinate it. Last grow I always checked input and output and recorded the results. Runoff EC was useless but the PH was always in the 6-7 range no matter what the input PH was.

1 Like
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I wouldn’t worry about any of the lower leaves at this point. Plant looks good.

I don’t know about the thin leaves and I couldn’t find anything specific with a web search. I wouldn’t worry about it. The plant does look a lot like the BB auto I grew two years ago.

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2 Likes
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This is a tad high. If runoff isbt suffering? No harm, but id adjust more into the 6.8 range

1 Like
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Gotcha… i will keep an eye on things and make sure it doesn’t progress upwards… thanks!

2 Likes
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I think i will adjust the PH down a bit, wont hurt anything… thanks for the help!

1 Like