Head scratcher - any advice appreciated!

Zelig · Dec 6, 2025

Hello all, on my second Grow. Two different clones have been fighting with yellow and dying leaves for the past three weeks.

Fox farm soil grow in 5 gallon pots. Running grow tent at 70° 55% humidity with exhaust fan and oscillating fans for airflow.

No insects on leaves or soil or on any sticky traps.

Water and feeding at 6.3 pH verified by two different pH meters.

Feeding once a week and supplemented the past two weeks with magnesium sulfate addendum (1 tablespoon per gallon) between feedings of Calmal (1ml) and General hydroponics floramicro (5ml) , Flora Gro (1ml)and floraBloom (3ml) per gallon. Lights running at 400 PPFD.

Have no clue what is causing this and not sure if I should abandon the Grow at this point and start over. Any help much appreciated! Copy the post other pictures if needed

juliando · Dec 6, 2025

Some thoughts - I think I have caused alot of problems dosing calmag in the past. Once in soil and once in hydro - Most fertilizers and tap water contain enough (or just about enough) for my plants. And my additions just made things worse - although your 1ml per feed doesnt sound extreme.

I had some low magnesium (Started feeding a little late) on my current grow that presented as a spotting/blotching in the center of the oldest leaves - but not a general yellowing like that.

I dont think youre at "give up" just yet, I have been consistently surprised at what plants can bounce back from (In veg state at least not in flower)
Good luck

ArtfulCodger · Dec 6, 2025

Taco-ing, edge curl, extensive purpling on stems and lighter color the higher up the you look...all suggest too much light to me.

Eledin · Dec 6, 2025

Yup, happened to me many times and its happening right now in my small indoors because I cant pull the lights higher and I dont wanna dimm them too much because the lower buds need light. In my case its under control but you should take meassures with the light.

JIMKSI64 · Dec 6, 2025

Same here. Last run same strain same everything but get over 40k lux on 18-6 and shit starts up this run.
I run fox farms soils and start up cal-mag when I push lights to 75% of expected maximum. For me it was week 2 flower and 30k lux.
3ml gallon rate as maint.
When treating for issues I use the higher 5ml per gallon rate.
Now if I could stop buying bags of gnants I be cool........

Ninjadogma · Dec 6, 2025

Yellowing in the middle of the plant like that is usually a salt accumulation problem. You've been testing your pH so hopefully you have an EC pen too. The next time you water, block an hour of your time and do the work to dilute the salts in the soil and break up any channeling or hydrophobia going on. However slow you're watering it's not slow enough. When I say block an hour to do that watering I mean it. Or get a watering ring or donut bladder with a 2gph flow rate.

Eledin · Dec 6, 2025

JIMKSI64 said:
Now if I could stop buying bags of gnants I be cool........

Fox farm?

Ninjadogma · Dec 6, 2025

ArtfulCodger said:
Taco-ing, edge curl, extensive purpling on stems and lighter color the higher up the you look...all suggest too much light to me.

Those symptoms are present too but the yellowing leaf underneath the greener one didn't get that way by light alone.

ArtfulCodger · Dec 6, 2025

Ninjadogma said:
Those symptoms are present too but the yellowing leaf underneath the greener one didn't get that way by light alone.

No argument here. But the light is outrunning the plant's ability to take up nutes, whether that's restricted by over-feeding, over-watering, under-feeding, or something else. When my car starts making screwy noises, I lay off the accelerator.

WinJr63 · Dec 6, 2025

juliando said:
Some thoughts - I think I have caused alot of problems dosing calmag in the past. Once in soil and once in hydro - Most fertilizers and tap water contain enough (or just about enough) for my plants. And my additions just made things worse - although your 1ml per feed doesnt sound extreme.

I had some low magnesium (Started feeding a little late) on my current grow that presented as a spotting/blotching in the center of the oldest leaves - but not a general yellowing like that.
View attachment 2574137

I dont think youre at "give up" just yet, I have been consistently surprised at what plants can bounce back from (In veg state at least not in flower)
Good luck

Calcium lockout burn, flush fresh water @ 6.3 ph right on the cool warm water temp 67-68°f . Get ur 10-20% runoff check ur ppm get it somewhere around 700 ppm this will also bring down ir ec, after each runoff check ppm/ec don't worry about the ph runoff that will keep changing. Ur next feed check ur npk ratio is good for plant stage. You might half to flush once more after next feed or go lower npk ratio .
My 2 cents this working for me. I had 1 leaf get fried from this of course I pumped up the ZNUTES!

Happy Smoking

Zelig · Dec 6, 2025

Ninjadogma said:
Those symptoms are present too but the yellowing leaf underneath the greener one didn't get that way by light alone.

That’s my feeling also. I lowered light intensity and raised a bit for now

Zelig · Dec 6, 2025

ArtfulCodger said:
No argument here. But the light is outrunning the plant's ability to take up nutes, whether that's restricted by over-feeding, over-watering, under-feeding, or something else. When my car starts making screwy noises, I lay off the accelerator.

That’s a great point. Didn’t think of that effect.

Zelig · Dec 26, 2025

Mystery solved. I don’t know why my light controller on “off” can have an on light value setting that is not off, but I somehow accidentally had “off” set to low level light, so basically my plans have had 24 hours of light continuously for six weeks! Removed all the yellow leaves and are stable again. I’ll flip them in a couple weeks and hopefully it won’t affect the flowering.

WinJr63 · Dec 27, 2025

WOW! That's messed up, glad you caught that, no more dehydration, grow on ladies !

JIMKSI64 · Dec 27, 2025

WinJr63 said:
WOW! That's messed up, glad you caught that, no more dehydration, grow on ladies !

Zelig said:
Mystery solved. I don’t know why my light controller on “off” can have an on light value setting that is not off, but I somehow accidentally had “off” set to low level light, so basically my plans have had 24 hours of light continuously for six weeks! Removed all the yellow leaves and are stable again. I’ll flip them in a couple weeks and hopefully it won’t affect the flowering.

I have an ACI product that does just that. Set the humidity to off but if you have a number for rate more than 0 it keeps fogging.
For a while a few Microsoft products would ask you 4 freaking times if you want to delete stuff. Would not mind a little of that from ACI.
If it's the same controller just wait till you bump the all button and pocket change to vdp for all inputs.
Might wanna set up some alerts to your phone. ACI and Vivosun will both send alerts if your tent numbers go out of specs that you set up.
Power tip. Set your phone up to run the alert until you cancel it not just park an icon on the screen.
Ok I was going to add the red alert sound board file from star trek to my phone but never could figure out how to make a custom ringtone repeat until turned off.

amneziaHaze · Dec 27, 2025

JIMKSI64 said:
I have an ACI product that does just that. Set the humidity to off but if you have a number for rate more than 0 it keeps fogging.
For a while a few Microsoft products would ask you 4 freaking times if you want to delete stuff. Would not mind a little of that from ACI.
If it's the same controller just wait till you bump the all button and pocket change to vdp for all inputs.
Might wanna set up some alerts to your phone. ACI and Vivosun will both send alerts if your tent numbers go out of specs that you set up.
Power tip. Set your phone up to run the alert until you cancel it not just park an icon on the screen.
Ok I was going to add the red alert sound board file from star trek to my phone but never could figure out how to make a custom ringtone repeat until turned off.

ac has a nice graph soo you can see if the line goes up or down indicating on or off

JIMKSI64 · Dec 27, 2025

amneziaHaze said:
ac has a nice graph soo you can see if the line goes up or down indicating on or off

Yes it does.
And if I put the screen in front of a magnifying glass I could actually see the trace line on 1

Zelig · Dec 27, 2025

I found that graph which helped me find out how long it’s been doing that on my AC system. It would be so easy to add an alert to the app if there’s a condition like keeping the lights on more than 24 hours that would pop up as a warning.

amneziaHaze · Dec 27, 2025

JIMKSI64 said:
Yes it does.
And if I put the screen in front of a magnifying glass I could actually see the trace line on 1

i got 3 lamps on it i do the sunrise crap as well and no problem with the line but maybe your climate is soo much changing that it makes it look far away :(
But you click anywhere on graph and it tells you at what power all of them are

LoveGrowingIt · Dec 27, 2025

Zelig said:
Mystery solved. I don’t know why my light controller on “off” can have an on light value setting that is not off, but I somehow accidentally had “off” set to low level light, so basically my plans have had 24 hours of light continuously for six weeks! Removed all the yellow leaves and are stable again. I’ll flip them in a couple weeks and hopefully it won’t affect the flowering.

I had a tough time wrapping my brain around how AC Infinity controllers have an 'off' setting that isn't necessarily actually off. I would've had better luck understanding terms, like 'low value' and 'high value'. That said, I tried running my light's power setting off the controller and eventually decided I prefer to use a control plug to just turn them on and off. That's because I'm always at the tent looking at the plants when I decide to change the light level.

Head scratcher - any advice appreciated!

Head scratcher - any advice appreciated!

Zelig

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