Can't figure out the problem...please help!

First post ever
Bubble Kush - autoflower --- LED lights 24/7 WEEK 6, DAY 41


Growing in a 30x30x60cm tent. Planted in a 3l plastic pot in soil mixed with perlite. Pretty airy soil. Plant got droopy & root bound around week 3, so I transplanted in 4l fabric pot. Didn't expect roots to develop that fast.

Always fed slightly, started with bloom nutes 2-7-4 mid week 4. Added Cal/Mag occasionally and had some periods when I only gave pH-ed water. Runoff water always around 6-6,5.

No droopy leaves after the transplant. But I have yellowing of leaves + brown spots as you can see in the pics. Most fan leaves I already removed because they were too damaged already.

Anyone has any idea what is happening? Didn't feed the plant for 11 days after first stress symptoms appeared. So I doubt it's nute burn of any kind. And I do let my plant dry out before watering.

Could only be some kind of deficiency. Showed pistils at the end of week 3. Now at week 6, day 41 since it sprouted. I def. have enough light, but it shouldn't be light burn because even lower leaves are affected.

As you can see in pics, this is affecting my whole plant. Started with cal/mag and bloom nutes a week ago after 11 days break from nutes. I suspected potassium or phosphorus deficiency. But the problem remains cus I keep cutting damaged leaves

Any suggestions on what I am doing wrong? Could it be light stress? Or is it deficiency & am I just being impatient?

Appreciate all the help and sorry if this got too long

BIGGER PICS! Sorry about that

How close is that light?

20cm, as much as it was in the beginning & plant was happy. It's homemade COB LEDs. Temps constantly around 25-28C

Started developing flowers + leaves on lower branches and they look happy. But the new leaves on top got brown/white spots as you can see in the pics.

So maybe the last 2 feeds did some good, but the damage is already done to the rest of the plant?

I don't have much exp. with stress recovery

Calmag. It's not going to fix the damaged leaves though.

What ph are you putting in?

I was putting in around 6, now more towards 7. Could be Cal/Mag. Didn't over do it. Fed maybe 4 times with Cal/Mag.

It could be that the damage is done & that I am impatient. But I really can't afford a mistake now. Do I keep feeding or not?

mj92 said:

I was putting in around 6, now more towards 7. Could be Cal/Mag. Didn't over do it. Fed maybe 4 times with Cal/Mag.

It could be that the damage is done & that I am impatient. But I really can't afford a mistake now. Do I keep feeding or not?

Click to expand...

I'm glad you bumped your ph up, it looks more like ph than calmag, but it could be both.

Those orange/red tips is what makes me think ph over calmag.

You have to feed, just fluctuate that ph between 6.0-7.0. I know a lot of folks will disagree but I think ph fluctuation within spec is detrimental to micro absorption. Keep on with the calmag.

In soil, your looking at a week of recovery.

If Harley tells you to move that light up, listen to him. He knows quite a bit about it and it does slightly resemble light burn.

Wait for him to advise on that.

Thanks for suggestions. I suppose Cal/Mag can't hurt. Definitely waited too long to take some action.

The reason I grow in such a small pot is because it's a really small tent So I will try with lights up, but not much space left. Will put transparent plastic panel under the lights. Should lower the light output by at least 10%

But definitely not heat stress! Could be just to much light, considering I ran them 24/7

mj92 said:

Thanks for suggestions. I suppose Cal/Mag can't hurt. Definitely waited too long to take some action.

The reason I grow in such a small pot is because it's a really small tent So I will try with lights up, but not much space left. Will put transparent plastic panel under the lights. Should lower the light output by at least 10%

But definitely not heat stress! Could be just to much light, considering I ran them 24/7

Click to expand...

It's possible. I don't run COB. I run HPS and LED, but my LED is just a maintenance light in reality.

In the pics, looks like the tips and some of that spotting is like an orange/red. Is that the case in person? That's what makes me think ph.

Around the flowers it's taking red/purple color. But it's not spotting, could be genetics? The rest of the spotting is brown & yellow/white.

As you can see, the branches & stem are purple at some places.

3rd Monkey said:

If Harley tells you to move that light up, listen to him. He knows quite a bit about it and it does slightly resemble light burn.

Wait for him to advise on that.

Click to expand...

And I do advise raising the light.

https://ledlightsnation.com/tips-on-growing-marijuana-indoors/

mj92 said:

Around the flowers it's taking red/purple color. But it's not spotting, could be genetics? The rest of the spotting is brown & yellow/white.

As you can see, the branches & stem are purple at some places.View attachment 4286131

Click to expand...

Yea, I'm going with ph. The purplish stems suggest phosphorus and the spotting and red/purple leaf tips I doubt are genetics (still could be) with the rest of the issues going on. Also the clawing.

I would say it's a bit locked out from the lower ph.

Well, the runoff water was at 6pH for a long time. I guess it's on the lower end for soil.

So I'll keep feeding bloom nutes (not over do it) & keep adding cal/mag. We'll see what happens.

Thanks guys!

mj92 said:

Well, the runoff water was at 6pH for a long time. I guess it's on the lower end for soil.

So I'll keep feeding bloom nutes (not over do it) & keep adding cal/mag. We'll see what happens.

Thanks guys!

Click to expand...

Make sure you have plenty of runoff on the next feed just to wash the roots off a tad. I'm sure you know that, but just a reminder lol.

mj92 said:

Well, the runoff water was at 6pH for a long time. I guess it's on the lower end for soil.

So I'll keep feeding bloom nutes (not over do it) & keep adding cal/mag. We'll see what happens.

Thanks guys!

Click to expand...

Are you allowing the medium to dry somewhat between feeds? Especially directly under the plant?

60+ hours between waterings in a 4l fabric pot. I am not over watering, no chance.

Meaning, yes I allow the soil to dry a lot.

Plus when I transplanted the roots were white & healthy looking.

looks like P deficiency caused by root rot or PH problems.

NwGKenny said:

looks like P deficiency caused by root rot or PH problems.

Click to expand...

I will flush it with high pH water, then feed it with pH@7. Should't be root rot. Runoff water smells OK, roots are white.

Thanks again everyone. I'll update in a few days