Fungus or a deficiency?

:weedpoke:notice the color on the mainstem,is it a big concern ?
Im been keeping the temp around low 80` and the humidity around 50,also have a fan circulating air

I don't really see anything wrong with the stem although the plant itself seems a little droopy but I'm not a soil grower...I do hydro. What kind of light are you using? Seems rather poor.

You need more light.
The red striping on the stem isn't as worrisome as the red petioles. = S def.
You need a fertilizer that contains micronutes.
Waht is that soil?

You need more light and more fertilizer. Stinky's eyes are better than mine, but what I see is plants that are spindly from lack of light, and that have poor-quality, somewhat yellow lower leaves, some of which have clearly already dropped. Classic sign of nitrogen deficiency. Also, I think I see a little interveinal chlorosis (yellowing from chlorophyll die-off) in some middle leaves. Probably the beginning of yellowing and death from lack of nitrogen. If you see that yellowing between the veins of the upper leaves, it's too much phosphorus. Miracle Gro 15-30-15 can cause that by overloading them on phosphorus (the 30), which causes a manganese deficiency that in turn limits the plant's ability to translocate nitrogen to feed the chlorophyll. If you see that on upper leaves, toss a little epsom salts on them and go to a fertilizer that's lower in phosphorus, and they'll be fine.

I don't know what the consensus is on what fertilizer to use on weed, but Stinky's right for sure that it should have micronutrients. And what kind of soil mix is that? It looks like mostly gravel and/or Perlite, not the sort of thing that would be naturally rich in those vital micronutrients.

The lack of light will also contribute to yellowing of the lower leaves.

Sorry, I meant to say magnesium, not manganese.

Quote:

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Originally Posted by ohkelly

Sorry, I meant to say magnesium,

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Nice call, lower RH corner, pic#3, first signs.

Yeah, but it's probably just the N deficiency making its way upwards, and only beginning to show on that leaf. Mag deficiency is actually pretty rare unless you OD on phosphorus. And it's usually on the upper leaves first because the N is trapped down below and the new leaves just don't get it.

Mg def I've seen in severely wet, acid soils too, or as part of a multiple-nute def/lockout. It ain't pretty. :D
I think tht leaf in pic 3- the striping is very regular and a sure candidate for a Mg def diagnosis.
lol where'd you come from all smart n shit? :D Nice to have you on board!

Sorry, I should have said that there's almost always enough Mg present. It's not getting it where it's needed in the plant that happens often enough, for various reasons. With me, it's almost always too much P.