P or Cal deficiency, or overfed. Not sure

Making my entrance to the forums because something is going wrong, as I'm sure most people do. Hopefully we can get this figured out.

OG Kush x Amnesia Haze, 21 days old
DWC, 630 CMH
AN 3 part fert. Was at 600 ppm, at 270 now to see if its nute burn. PH 5.5-6.0
76 degrees, 60% humidity

When they were really small, I forgot to add Bloom, so they had no P. Fixed that 9 days ago and they took off growing.

Now I'm getting brown patches on the lower fan leaves of one plant. My biggest plant. The other one in the same reservoir is growing fine. Any ideas what it may be?

Over 3 days I've dropped nute strength from 600ppm(500) to 270ppm. In 24 hours it has only gotten worse at the lower ppm.

Looks like a high pH to me.

Possibly. Your not showing any tip burn which makes me think it is because you are underfeeding them. Me, I would buy some calmag, calmag your water to 150ppm above the baseline. Do everything else you been doing, use your three part to add around 300-400 on top of the calmag. Keep an eye on what your PH is doing. What is your PH and PPM doing overnight btw? Dropping? Rising?

5BY5LEC said:

Possibly. Your not showing any tip burn which makes me think it is because you are underfeeding them. Me, I would buy some calmag, calmag your water to 150ppm above the baseline. Do everything else you been doing, use your three part to add around 300-400 on top of the calmag. Keep an eye on what your PH is doing. What is your PH and PPM doing overnight btw? Dropping? Rising?

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My PH drops a couple of points every day. Once it hits 6 or 6.1 I try to bump it back to 5.5. PPM seems to rise 10 every day. Its only been a day since I really dropped the nute strength though.

The other plant in the res is growing just fine, and the 2 in the second rez are also growing well at 530 ppm. The plant with issues has much bigger, thicker leaves than the rest of them. Makes me wonder if it's "special" in its requirements.

I'll see how they look tomorrow, and then I'l try your recommendations if I don't notice any improvement.

Thanks for the response

Probably not a root thing. Rdwc? If your using ph down everyday that would be my guess as to why.
600 is low. Some plants will do ok but some just demand more
You’ll find your ph will stay more stable once u up the nutes. 1000+. Works for me anyway.
Good luck.

Here was one that looks similar to yours.At the time ph wouldn’t settle.upping the calmag and nutes fixed it.

Thanks for the idea, Myke. I gave her a CalMag foliar feed yesterday, and mixed up a new nutrient batch. Just have give her some time to respond now.

That's a pretty huge PPM drop...if you were overfeeding, then it's possible by doing such a big PPM drop that you're now underfeeding...no clue if that's the case, just saying back off of the PPM's less when trying to decipher if your plant's comftorble with it's nutrients. Back off maybe 100-150 instead of 300ppm. Give it time to see if the Cal/mag affects it, then we can go from there If not, then it's one cause crossed off the list! A ph of 5.5-6.0 sounds perfect, have you calibrated your PH meter in awhile?

Logan Burke said:

That's a pretty huge PPM drop...if you were overfeeding, then it's possible by doing such a big PPM drop that you're now underfeeding...no clue if that's the case, just saying back off of the PPM's less when trying to decipher if your plant's comftorble with it's nutrients. Back off maybe 100-150 instead of 300ppm. Give it time to see if the Cal/mag affects it, then we can go from there If not, then it's one cause crossed off the list! A ph of 5.5-6.0 sounds perfect, have you calibrated your PH meter in awhile?

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I had dropped the ppm a couple times every day before I ended up where I was. PH meter is calibrated.
My other 3 plants look fine, it's just this one that is acting up. It seems like the leaf necrosis is worse in direct light, and its only affecting the older leaves. She also has some clawing happening as well, maybe from the new solution, which is 610 ppm.

myke said:

Probably not a root thing. Rdwc? If your using ph down everyday that would be my guess as to why.
600 is low. Some plants will do ok but some just demand more
You’ll find your ph will stay more stable once u up the nutes. 1000+. Works for me anyway.
Good luck.

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For me, 600 was high. If I went over 600 in full flower they would throw tips.

Geez my clones once rooted get more then 600. Some like the low ppm I guess.The plants will tell ya what they like.

Your calmag has N so consider that when thinking about the clawing.
Can you post pics of the other plants? AN should be the same NPK as GH, which I use. What are you running for ratios?

myke said:

Geez my clones once rooted get more then 600. Some like the low ppm I guess.The plants will tell ya what they like.

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Damn. Just goes to show the huge difference. I think in dwc,rdwc it has a lot to do with how much O2 one is pumping in. More air less nutes.

I'm going with P def. The leaves are showing it, the stems are showing it (purpling), and you said you weren't feeding it any P. Have you flushed recently?

If not, I would flush with a good ppm (whatever you were doing) with a good dose of P.

It's working it's way up the plant... Better move quickly.

How about other things like water temp or night temp?Roots are they white?Hows the smell?Lots of air?Any slime on your air stones?Sounds like your doing everything right.
Not familiar with your nutes so cant help ya there.

Water temp is 66-68 right now. Not sure on night temps. Probably around 68, same as the basement.

Roots are pretty white, no smell coming from them.

Might it take a couple days for the damage to stop after changing nutrients? Its still spreading, but seems to be slowing. Might foliar feed it again if it continues.

Two other plants are perfectly healthy, one is slow, it almost died when I forgot to add the Phosphorous a couple weeks ago.
Might just gave to give it a bit and see it things change now.

48 hours and you should see those symptoms start to slow, if you fixed the problem that is.

Duellie said:

Water temp is 66-68 right now. Not sure on night temps. Probably around 68, same as the basement.

Roots are pretty white, no smell coming from them.

Might it take a couple days for the damage to stop after changing nutrients? Its still spreading, but seems to be slowing. Might foliar feed it again if it continues.

Two other plants are perfectly healthy, one is slow, it almost died when I forgot to add the Phosphorous a couple weeks ago.
Might just gave to give it a bit and see it things change now.
View attachment 4285467 View attachment 4285468

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Yeap, if the problem is corrected, you should see that the symptoms stop spreading inside of 48 hours. Perks of being in DWC, we get to see quicker responses from our plants! I must say, this one stumped me a bit with the other plants being in that same res, being the same size and (I'm assuming) the same strain. But I have had phenotypes of a single strain come out in one plant and not another, making their nutrient sensitivities a bit different than the others. The plant on the bottom right in your last post is the plant affected, right? Anyways, yeah definitely give it a few days before adding more nutrients just so you can really see the cause and affect. If the symptoms are slowing, we're on the right track
*EDIT* Also meant to add, if your PH is rising over night then this is a good thing! Your plant is eating it's dinner and in my experience means you can try upping the PPM's after your plant has made a full recovery.

3rd Monkey said:

I'm going with P def. The leaves are showing it, the stems are showing it (purpling), and you said you weren't feeding it any P. Have you flushed recently?

If not, I would flush with a good ppm (whatever you were doing) with a good dose of P.

It's working it's way up the plant... Better move quickly.

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Ok, so I think you're onto something. The purplest petioles are on the really damaged leaves, the newer leaves have no real purple on the stems, and the sunniest leaf of a pair will die much faster than the one in the shade, which I read somewhere is something a lack of phosphorous does.

Maybe the lack of P from the beginning made me think my plant had a purple tinge to it. Maybe these giant leaves need extra P to operate at max capacity.

My plan...pull 10 of 70ish Litres of nutes out to remove some N, replace with 10L diluted Bloom to put the ppm back. Light foliar feed with Bloom, and wait...

Duellie said:

Ok, so I think you're onto something. The purplest petioles are on the really damaged leaves, the newer leaves have no real purple on the stems, and the sunniest leaf of a pair will die much faster than the one in the shade, which I read somewhere is something a lack of phosphorous does.

Maybe the lack of P from the beginning made me think my plant had a purple tinge to it. Maybe these giant leaves need extra P to operate at max capacity.

My plan...pull 10 of 70ish Litres of nutes out to remove some N, replace with 10L diluted Bloom to put the ppm back. Light foliar feed with Bloom, and wait...

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I don't know what's in your res, but you do, so get it done. Luckily, P is mobile so it'll perk up fairly quick. The damage that's done is done.

Just keep an eye on your EC.