Yellowing problem, cannot figure this one out

[chrononzon]

That's either Potassium or Magnesium deficiency from what I can see in ops pics.
Are leaves drying at tips/ edges or curling at all?


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no drying at the tips.
the yellowing is really up top. The pics are not great.

We thought it was light bleaching maybe and reduced power. V CONFUSED

[Karsa]

no drying at the tips.
the yellowing is really up top. The pics are not great.

We thought it was light bleaching maybe and reduced power. V CONFUSED

Can you provide a better quality picture maybe of some of the turning leaves and the really bad ones? Ngl man the pics aren't ideal so if you want more help, help us help you.


Feed maybe weak if it's every other feed meaning you've a lot more deficiencies than is obvious at present. Based on the pics alone I'd honestly say it's a toss up between magnesium and potassium... I doubt it's manganese but I could be entirely wrong here. But seems you're adamant it's not magnesium... So can't really help you till better pics are provided

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[chrononzon]

thanks mate, will get more pics right now.

We have been v v careful with nutes.

Not meaning to be adamant about anything. just would have expected yellowing lower down.

the yellow leafs with green veins really do look like some pics i've seen online for mag def

[Karsa]

Potassium deficiency: the edges of the lower, outer leaves begin to turn pale yellow, while the veins remain green. The leaf tips and edges may become dry and brown and begin to curl up or down.

Magnesium deficiency: similar to potassium but In the early stages, the leaf edges begin to turn yellow while the veins remain dark. As the deficiency progresses, the leaf edges start to dry out and curl inwards eventually working up the plant to new growth

Just to throw these into the mix too...

Sulphur deficiency: rare one but looks a lot like nitrogen deficiency in the early stages, as it causes the entire leaf to be pale and chlorotic, with very slightly darker veins. However, sulphur deficiency usually affects the newer leaves first, unlike nitrogen deficiency. It also affects the back of the leaf first before progressing towards the tip, unlike many other deficiencies.

Manganese deficiency: also rare, and shares several points of similarity with sulphur deficiency. In the early stages, leaves will begin to yellow, leaving slightly darker veins. The yellowing often occurs at the base of the leaf, before spreading out towards the tip. As the deficiency progresses, brown, necrotic spots will begin to appear all over the leaves; these spots will spread throughout the plant if it is not corrected.


The original info is not mine

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[chrononzon]

we were sure it was light burn but I just cant see that now.

we have def been a little stingy careful with nutes.

i'm thinking 2 actions.

1. hearty nutes with next water, 4ml per litre and some mollasses
2. a weak cal/mag solution spray test on a few leafs of one plant only

will report back any findings

[chrononzon]

latest pic. ....... currently pots are nice and light and getting thirsty.

raised LED height and lowered power

tent ; temps 24 humid 65

warm room 23

[chrononzon]

the last pic is awful. the plant is not as yellow as that. will take better pics tonight

[Karsa]

Nab a lights off pic mukka, flash is fine

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[Loki]

This may come over a little controversial, but with certain water, the background EC could play a small role in soil. My thinking is that when I grow in coco, I occasionally leave my coco to get a bit dry, this often causes build up of the left over dried salts. Come the next feed, those dried salts will dissolve and cause small hotspots of nutrients, which I think could cause a lockout and give misleading side effects.

Depending on your location, hard or soft water may determine the levels at which you need to feed the plants.

My background is 0.7, often leading to problems with high levels of limescale in my water.

Maybe you could take measurements from the first 100ml or so from the runoff from your pots, using pH and EC meters, I often tested the runoff from soil and sometimes got high pH or EC

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[chrononzon]

Nab a lights off pic mukka, flash is fine

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still need to get that pic. Will be back with it.

so, last night i gave a strong nute solution with 1mg/l calmag

They already look better with more green and less yellow.

will await another 24 hrs before i feel out of the woods.

Still reallly not convinced the cal mag helped. So confusing.

really cannot be more critical of Biobizz nutrient and product schedule. It's like following a sequence of dreams over a 72 hr Ibogaine ritual.

So many contradictions in their feed schedule.