New Grower Heavyweight Auto Cal Mag deficiency ?

[Peter Pan]

Hello AFN this is my 2nd Vast & Fast in day 20 under 100watts cfl in a 15 lit pot. Its about 10 cm tall but has already develop the 6th node, Today I noticed a strange leaf which reminds me of mag deficiency Am I wrong? Can I add B 52? What do you think friends.
Thanks a lot.

 

[Weedman30]

The first Photo bottom Leafs almost look like Phosporus Deficency. And second Photo the leaf has darkened curled up and died.

Thencenter of the Leafs are turning dark working towards outer leaf correct? Kinda brownish blackish?

 

[Peter Pan]

I see the fibers of the leaf turning darker than the other leaf, and yes it continues outward. what should I do?

 

[Peter Pan]

this is what it reminds me, but again iam a noob and this is phosphorous Iam confused please your advice friend

 

[Weedman30]

What's your Soils PH?

Phosphorus is locked out around the PH Range of 4-5 Or over 7

Also your soil could be to compacted to wet or cold this all will cause Phosphorus Deficency.

What Nutes are you Using has she been fed?

 

[Weedman30]

It could be Mag as well. But the Bigger Areas of Purple Black in my experience have also been Phosphorus def.

Give a nice feeding of any Organic Nute with a N-P-K of 5-5-5 or over at half strength or so and it should help that def.

 

[Peter Pan]

Thanks mate