Please help: dark brown/black spots on leaves

Please help! Got some Skittlez Auto seeds from ILGM. About day 50 in coco coir with 25% perlite for this girl. First time growing. 3 gal cloth pot.

Organic dry amendments: Dr Earth 4-6-3, bud n bloom, worm castings, some sea bird guano. Mycorrhizae added. Running the EVQ QBS1000. About 15 in away at full blast. Just moved her under this light so these spots were forming before this light. Had her under ViparSpectra 600w.

I just started adding molasses to the water. I water about every other day. Ph of runnoff last I checked was almost neutral- 6.9, which I thought was a lil on the high side?

Anyway, temps are 75 during lights on, 69 off. Humidity won’t get over 55 with lights off. 45-50 rh with lights on. 4in Carbon filter in a 27x27x54in tent. Ac infinity duct fan pulling air out of tent.

I can’t quite find anything that resembles these dark spots on my leaves. What do you think?? Let me know if you need more info. Thanks for your help!

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That is too high for coco. What ph are you feeding at?

I use 2 ph meters to measure because I feel they are unreliable. I calibrate them often enough. I stay in between 6.5-6.8 but mostly get as close to 6.5 as possible. Think I should bring that down a bit??

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It’s ok to let your feed ph drift in coco between 5.5-6.5 but you’ll want to aim mostly around 5.8. Are you feeding until you get a good amount of runoff? With coco you should be feeding at least once a day

Okay sounds good. However I have to ask, in my research (again, I’m a newbie), especially for an organic dry amendment grow, it’s better to keep the ph of the water around 6.5? I thought a ph of 5.8 was more for a liquid fert/fertigation set up.

Same thing goes with the “feed till runoff”? I thought that was more for liquid fert feedings too because it gets rid of the salt build up. In my organic dry amendments grow, there is no salt build up. I feel like I’m treating the coco more like soil (and idk if that’s good or bad).

I appreciate your advice big time. Thanks for your help.

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I missed the organic part . Good catch . I’m not familiar with organic in coco so I’ll have to defer. I can recommend a great resource site for coco growers , tons of info.

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Okay thank you! Am I allowed to repost this question? Or are others still able to potentially answer? Lol sorry I’m just trying to get some insight on these dark spots on the leaves…

Looks like you have some nitrogen toxicity going on.

Ohhh snap. It could be. I re-amended after 20 days at that could be too soon. Any remedies? Or just ride it out? Maybe it’ll straighten out on its own?

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I don’t want to advise you there as I’m a salt fert guy. @shindig153 I’m pretty sure that guy is organic. I’m not sure who else to tag for you. I imagine your best bet is to just ride it out and live and learn. Somebody who knows more than me will be along.

Others can still see your question :v:

To be honest I couldn’t tell you, I’m organic soil/soil-less mix but I haven’t used coco.
I never used that dry ammendment, but
I always, always, always use kelp meal when building a soil. It’s got like 13/16 elements plants need, even out your npk with meals like crab/neem/bone, etc. Personally I ph down with a brix molasses every time. It takes less molasses and feeds less sugar to the soil/microbes at a time.

I top dress using dry ammendments. There is a cycle to the top dress. A week before the flip , about 3 weeks into flower and maybe lightly again at about week 6. I don’t really pay attention to my ph or ppm because I’m in soil and use lime to buffer.

I’ve never used coco so I’m uncertain about your ph. If it were me I’d try to keep my ph much lower than you have it. I’m thinking that you still need to keep the coco in the same ph range regardless if you’re using chemical fertilizers or organic.

I’d also raise the light a little. I’ve made the mistake of pushing my plants too hard with light right off the bat. Also turn the light down and work the intensity up to full blast. I have hlg light and hang them at the top of the tent and let the plants grow to them. It’s not what most do but I perfer it. I run my lights at about 85% the entire grow.

Thanks so much for the responses. I’m going to adjust my ph for my waterings slightly lower. Probably shoot for 6.4 the next water, then 6.3, and see how she responded and go from there. I’d hate to ph 5.8 right away and have her get mad at me.

I think there’s a slight nitrogen toxicity. The leaves are pretty damn green. And shiny.

I don’t have any lime, or kelp meal. But I will be getting some for the next go round. I will update just for shits and gigs in a couple weeks to show how she’s doing (if that’s appropriate for the forum).

This forum is awesome. Thanks so much!

Happy growing

Welcome to the forum. I missed that this is your first post.

This is your journal to document whatever you want. I’ll set to watch so when you post an update the system will send me a notification to take a look.

Just under the reply button there is a grey box that says tracking. If you want to follow someone you click on that and a screen comes down with options. Set to watch to follow along.


I’ll tag you to my journal to read through. I started with super soil but moved to a living soil. Lots of good info there for organic growing.

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@Happy-grower20. Welcome! Great people here to to help you! I am in my first grow and they have been tremendous with their advice and encouragement.

I am going to tag along myself. I have 5 strains going and they all have issues.

@shindig153 thanks so much! I’m going to give your journal a read for sure. Looking forward to it.

Of course @JaneQP, follow along!

I’m happy to be here. This place rocks

Update 1 day later:

It’s getting worse. But I don’t think it’s going to be a major deal. The pics are below but the brown spots are getting worse. I definitely think I top dressed too soon and now have too much organic dry amendments in my coco. Is that even possible??

I just watered tonight, ph between 6.35-6.5 and checked the runoff. It was ph 6.85-7.00! I really feel like for an organic grow using these dry amendments, that’s too high. Anybody have any knowledge about this?

Welp, live and learn. I wouldn’t call it a flush, but I wonder if I watered maybe 3x more as usual for a couple waterings if that would help pull some of the nutrients out of the coco and into the runoff, in which I would suck up with my turkey baster? Lol

I feel like doing nothing is bad, but maybe that’s best in this situation. Maybe I can’t fix everything.

Also, what do you think about leaf stripping? I would say this is week 2 of flower for this Skittlez Auto from ILGM. I haven’t leaf stripped and figure I don’t need to? Or lollipop? When should I do that?

Lots of questions. Appreciate your feedback.

I would get the ph correct fast as she is already mad and needs help fast.
Raise your light up as well. I dont want to be the one to point out the obvious but there is way more wrong than just spots on leaves.
Its clawing edges of leaves probably from light to close. Its Droopy and has to much nitrogen probably from ph imbalance.
And I’ll guess watering improperly.

But dont freak out, easy fixes and it should be fine if addressed.