I can not nail the Identity of this leaf problem.

[Weed Pharma]

This Indica (Green Love Potion-Nirvana freebie) is 41 days post germination and in 12/12 lights for the past 5 days-
Growing well in Roots Organic Original (amended) with only protekt added through out the grow.
run off pH @6.2 with normal watering patterns.
Neemed a few times before the 12/12- no pests- etc.
The plant always looked healthy and is growing fine- @ 12" tall and filling out nicely.
The plant was sensitive to both heat and light stress, but recovered quickly once adjusted.


My first impression when this started a few days ago- was nitrogen deficient- I was holding off (waiting to try flowertabs from Nirvanashop due here, anytime).
As things progressed it started to look more like a potassium deficiency as it spread. (yet potassium is the only nute I ad- for pH adjustment)

All yellowing is on the bottom main stem, large fan leaves with new growth everywhere looking fine.

Is it simple nitrogen deficiency (in slow motion,lol) and it's trying to hold on? As I usually address and stops progressing.
Is it something else I am not even thinking about?

[Royal Nugs]

Looks like the plant is cannibalizing the lower growth. You need to increase your feeding strength and/or trim that lower stuff. Nebula has a great section on pruning.

[Mañ'O'Green]

It looks like a combination of zinc and magnesium shortage but the burned tips are usually from too much nutes? that may have happened a while ago?

[Weed Pharma]

I have not added any nutes yet, but the burnt tips have been there-

It happens on occasion with seedlings grown in Roots Organic Original. I have heard of it being too hot for seeds- but have good results so far!

[Weed Pharma]

The soil has been amended and no additional nutrients have been used.
I have a sativa further along doing fine (pic)- but suspect its time to add a feeding to both plants if the flowertabs don't arrive today.
Since it very well may be cannibalizing itself, I'm glad I don't trim until the 1 & 3rd weeks in flower (this Indica is in week 1).
As a rule I do not defoliate sativa's and it's in week 3 of flower with very slight leaf loss.

[kingfish]

I have had the same issue with my tips looking burned when I've never given it any nutes. I also use Roots Organics and suspected the soil. Now I know. You guys rock.

[Weed Pharma]

UPDATE: flowertabs arrived and I added 1/4 (4-5g) to each plant and decided to add 1ml Dyna-Gro Bloom to the Indica which was in the worse state.

Now we wait!

[Mañ'O'Green]

If you think the soil is too "hot" for seeds just pot a 5" layer of seed starting soil on top of the ROO and water with a 20% nutrient system for the first couple of weeks. By the time the tap root gets down into the ROO the plant will be better able to use the nutrients there.

[NebulaHaze]

Just curious, is it just the leaves on the bottom of the plant seeing these symptoms? Is it possible that these leaves are in shadow now that your plant has gotten a lot bigger? The reason I ask is because I've noticed that the plants often seems to "give up" on leaves that are located at the bottom and aren't getting light any more. They commonly get sort of wilty/droopy and get deficiencies. If it's only happening to those leaves and not anywhere else on the plant, I wouldn't worry too much about them, especially if it's not spreading.

[Weed Pharma]

That's exactly what is happening on both plants. The plants otherwise look fine on all levels to me. I did add 1/4 flowertabs (Nirvana) to supplement at this point. Something was just not right about, how it looked, how it progressed etc- from normal nute deficiency I have observed in the past.

Previously, I have seen what appeared like clawing (sativa)- and once turned for better lighting/less wind it never progressed (yellow etc) and seems to have improved although the leaves are still very dark. The sativa was heavily HST-LST in an upward spiral- placed inside an inverted tomato cage and Fimmed. (it grew too tall while I was away in August).

I'm not a fan of side lighting (mostly because I build a canopy) and in this case, I don't think it would affect the final product - as both issues show up on leaves most would defoliate anyways!

[NebulaHaze]

Yes, I wouldn't worry about adding side lighting when you have good light coming from the top! It's natural for the plant to lose some leaves as it grows even if you're the perfect grower, and like you said, I especially wouldn't worry about leaves that are going to be defoliated anyway when the rest of the plant looks great!