potassium deficency?

[exer]

Is this potassium deficency causes by low relative humidity?
All plants are in 4x8 ebb and fow tabel in pots with hydroton,ph is 5,8.It is very strange because only the plants that are close to dehumidifier get deficency.

 

[ExEcutioner]

what media is that... that the plant was transferred from that's around the roots? coco?

 

[Sat X RB]

I think yr plants are showing "senescence". that is: nutrients are moving from the leaves into bud sites as the plant ends its growing cycle. too late to pull the plant back with altered nutrients. the grow is finished.

 

[exer]

Hi guys

I still have the same problem,i just cant figured what is causes the problem.
I have this problem every round,it starts at begining of week 5 of flowering and becoming worse and worse till week 9.it stars at lower leaves and goes to the top.
When leaves die,also the bud related to this leavs die.

I use floranova bloom,some extra PK,ph 5.8, tems. 28 C humidity 40 %

 

[Ratzilla]

That looks like a iron deficiency to me.
Common when the pH is above 6.5 and uncommon when pH is below 6.5.
you see how the interveinal chlorosis starts at the base of the leaf instead of the leaf tip.
That is a sign of a Fe deficiency.
Fe deficiency is sometimes traced to a excess of copper.
Ratz

 

[exer]

Thanks for answer,i realy don t know why is this happening.i gorw with the same system for years,and didn t have any problems,but now i replace a location,and the problems starts.
I grow in hydro ,my ph is always 5.8
I still think that my Rh is too low.When RH is too low to grow and causes problems?
Here are some more pictures

 

[Ratzilla]

This last set of pictures look quite different to me?
A clue on what this problem maybe is told where on the plant are these leaves showing.
If its on the bottom then that is a sign that a mobile nutrient is involved.
If on the top that is a sign that it is a immobile nutrient.
I see where you say it starts on the bottom and progress upward.
This could be a clue that it is a mobile element.
Lets look at mobile elements.
Nitrogen, Phosphorus, Potassium, Magnesium, and Zinc.
Of all of these this last set of pictures resembles most Mg.
Other signs of Mg. deficiency are irregular brown spots on older leaves.
Leaf tips turn brown and turn upwards
Spots and yellowing envelope entire plant.
Leaves dry and die.
Did you say that you are in a coco base medium?
Many times a Ca. or a Mg. deficiency can show up when using coco.
It is important to note that Potassium competes with both Calcium and Magnesium for uptake.
If having to much K can fill the CEC with K allowing one or both of Ca. and or Mg. to be displaced.
Did you know that as coco coir breaks down it is constantly releasing potassium.
If using coir as your medium amend the medium with fertilizer that has less potassium.
A quick way to see if indeed that magnesium is deficient is to foliar some Epsom salt onto the leaves.
Heh heh heh but if you have many bud sites that might not be a option.
You could always water with 2 tsp./ gal
Look for greening to start from the top down
Another note a medium that is kept to wet/cold will make Mg. unavailable.
I am only here to help guide you.
You look like a very competent grower and I always say only the grower truly knows much more then anyone else can discern, for you know exactly what you did.
If you keep doing the same thing the same results will keep happening.
Its up to you
don't make to many changes at once for you could become the dog chasing his own tail.
I can see you have much style.
I am sure you will figure it out.
Ratz
I went back and re read your thread.
I see you grow in hydroton and are a hydro grower.
While some of the information that I posted will still apply I am a organic grower growing in a coir base mix.

 

[exer]

thanks Ratzilla

for this information,it could be a Mg deficiency,because first signs,when problem starts is that older leaf tips turn brown and turn upwards.I allso spot some irregular brown spots on some plants.
It s weired because i didn t change anything in my growing style.As i said,i only change location.Maybe is different water that i use.
I Will try to add some extra mg.