Yellowing tips of the leaves, help

Hi,

I’m growing Cream Caramel Auto in 2 gallon pots. It’s my second grow and I have the same issue as I did the last time - the tips of the leaves are yellowing. The plants are not showing any deficiencies or problems rather than yellowing at the tips on the new growth. The problem started at about day 30.

My growing medium is Biobizz lighmix + perlite + mycorrhizal fungi supplement. I also have Biobizz nutrients but until this day I only fed once and probably gave them only 1/4 of the recommended dose (+ some CalMag) at day 35. Soil pH is at 6.8.

My grow space is 2x1x2 ft (micro grow). I’m using 90w 2700K CFL + 76w 5500K CFL + 70w HPS. The distance from the bulbs is 6-8 inches.

I’m pretty sure it’s not a nutrient burn. Might it be a light burn? I doubt that because of CFLs... Also some tops are not yellowing. There’s no difference between tops at different distances from the lights either...

Zinc deficiency? They definitely got some zinc when I fed them.

Could it be something else?

P.S. Sorry for my English, it’s not my first language.

Ignore it ....... it’s from the hormonal changes going into flower.

Nothing to worry about; carry on and good luck friend. If you watch, as the new growth matures, it will green up.

Thanks for the input guys.
However, the problem seems like it is spreading... I see yellowing at the tips on the lower leaves, also I can see some browning at the very tips of the leaves where the yellowing started. Something is not right... The common sense tells me it might be a nutrient burn but that does not make any sense because I only gave them so little like .5ml/l of both grow and bloom at day 35, around 400PPM in total. And the yellowing started even before their first feed. Could it be that mycorrhizal fungi is doing it's job too well and any ammount of additional nutrients is causing leaves to burn?

Maybe a close up of the whole plant and bottom leaves as well,might help with diagnosing the problem

Budzbuddha said:

Ignore it ....... it’s from the hormonal changes going into flower.

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I did not know that. Thanks

Never got yellow tips from “hormonal change” but yellow tips are pretty common and usually nothing to worry about.

Some photos.

It really looks like a nutrient burn but the problem started even before the first feed and I'm also using lightmix...

Today is 14th day of flowering. I just gave them some plain water + CalMag 1ml/l at 6.3 pH @ 243-334 PPM (I have two TDS meters which both shows different numbers).

The runoff was:
1st plant) 6.8pH @ 360-486 PPM
2nd plant) 6.5pH @ 298-393 PPM

The plant with higher runoff PPM is also the one who is appearing more sick.

If “med-man feeding chart” is correct I should blast them with 800 PPM at this stage of flowering so it’s definitely not overfeed what’s causing leaf tips to yellow and brown…

I'm wondering if it's mycorrhizal fungi what's causing that... I put a lot of it in my soil mix but on the package it said that you can not overdo it...

Some yellowing at early flowering happens ... as it switches gears from fan making and branching to budset and flower.



Since you are probably finished with stretch at this time or at least slowing. You should be on a lower nitrogen “ bloom feed “ from now on. The leaves show more than enough stored in leaf ( dark / tip ) ... the nitrogen use will drop significantly around week 6 of flower as any new branching is pretty much over and Bud bulking is happening.

Plant will burn through excess as weeks go on. And will be looking more for P and K.
Hence the fading as later weeks come. Also early yellow can come from too early bloom nutes too.

Budzbuddha said:

Some yellowing at early flowering happens ... as it switches gears from fan making and branching to budset and flower.

View attachment 4319872

Since you are probably finished with stretch at this time or at least slowing. You should be on a lower nitrogen “ bloom feed “ from now on. The leaves show more than enough stored in leaf ( dark / tip ) ... the nitrogen use will drop significantly around week 6 of flower as any new branching is pretty much over and Bud bulking is happening.

Plant will burn through excess as weeks go on. And will be looking more for P and K.
Hence the fading as later weeks come. Also early yellow can come from too early bloom nutes too.

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What kinda camera was used for that pic? a potato lol

Yeah ... IPad Tato .

I had the same thing but it did not cause me any problems. That yellowing is so slight on the tips. Those leaves are healthy and your bud formations look good for day 14. So don't sweat it. Like Budz said, probably just the change. Maybe ever-so slightly hot on the mix but again its so slight I would not sweat it.

My plants during a very similar stage as yours. Notice the tips. Ever-so slight.

5BY5LEC said:

I had the same thing but it did not cause me any problems. That yellowing is so slight on the tips. Those leaves are healthy and your bud formations look good for day 14. So don't sweat it. Like Budz said, probably just the change. Maybe ever-so slightly hot on the mix but again its so slight I would not sweat it.

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5BY5LEC said:

My plants during a very similar stage as yours. Notice the tips. Ever-so slight.

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Mine was as yours few days ago but then it got worse, those yellow tips started to brown... Every time I check my girls, I see new tops affected. Runoff was only about 400 PPM so I doubt it's because of hot soil. How lightmix could be too hot especially after 6 weeks of growing in it?

I wouldn't sweat because of yellow tips, I'm worried because those tips started to burn and this is not normal.

It's my second grow of the same strain. This time my stems is quite weak, I accidentally broke a few when LSTing, which has never happened to me before. Also plants streched waaay more.
And they also have literally no smell which is strange because last time I've grown this strain, my room was reeking of weed at about week 3.
Some lower leaves are also dying, but that's probably because of not getting enough light.

I've read that potassium deficient might cause tips to yellow and brown, also weak stems and streching, could this be it?

In some of your pics the leaves are really green, like the first pic of the batch of pics you posted you can see the leaves are a really dark lush green.... so I would say Calcium toxicity which is probably locking other nutrients, so it's probably the calmag that's doing it

If your tips yellow they are gonna brown soon after, they wont stay yellow for long.
If your top leaves start to stripe or develop large spots, then I would worry.
Are the buds growing?

5BY5LEC said:

If your tips yellow they are gonna brown soon after, they wont stay yellow for long.
If your top leaves start to stripe or develop large spots, then I would worry.
Are the buds growing?

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Aaand they started to stripe, it looks like Mg or Zn deficiency... Only the top leaves affected so I would guess it can't be Mg deficiency, especially after feeding some CalMag.

Bud growth seems ok.

F@*k Biobizz soil. It's my first and definitely the last time using it. For the price I paid (17€/50l bag) it is definitely not worth it. Last grow I did in a really shitty soil mix made by myself, overfed 2 times and flushed like 3 times in a row and still had less problems with it. Too bad I can't get my hands on PM or other well known brand soil mix, all I can get is Biobizz or Canna Terra...