Terminal calcium deficiency?

Kassiopeija said:

that's wrong, Ca cannot be re-mobilised (better: retranslocated) which is the reason why a Ca-def results in stunted chlorotic shootgrowth, the necrotic spots appear somewhat later when the leaf becomes dysfunctional. And why you need a steady supply of Ca in water.
Mg is mobile and that's the reason why it's taken from the older leaves. In times of need, plants disassembles lower chlorophyll, attach the minerals to transporter-proteins, and feed these into the phloem where they can travel up or down.
But pH problems (xylem not neutral) can actually "sabotage" the ability to retranslocate nute-ions, then mobile nute defs can also appear mid or top the plant. The xylem's and phloem's pH is apart by +-1.5 - 2.0 and this creates a "pressure" to make it possible.


only in the case of photodestruction from too high irradiance, then - and with a true Mg def, the leaves will show striped chlorosis, unlike N or S def, which will affect the complete leafcolour

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Billy the Mountain said:

Calcium is immobile so it will NOT be moved from old to new growth.

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HydoDan said:

Medium? PH?

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waterproof808 said:

Have you looked at the manufacturers feed chart at all? You dont need the protekt or the zyme, but they want you to still use grow and calmag during flower.
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swantip said:

So the verdict is that i should use both epsom salts and calmag at the same time?

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swantip said:

24-25C(74-78F) rh:55-60% but i had humidity problems early on,before i go and buy a humidifier. 600W HPS. I also have an oscilating fan which blows on the top of the cola a bit,I dont have any more room to fit everything.This is an autoflower and its growing very vigorously its 115cm(45in) and only 40 days since sprout,so this really surprised me.

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Nutty sKunK said:

Did the humidifier run out for any period of time?

Usually that burn chlorosis on upper fan leaves is a combination of things. Most likely being low humidity spikes, increased wind, high intensity light, dry media (EC spikes).

It can be one or all of those things. I’d up the calmag slightly as budding is coming. Autos seem to like a lot of cal very fast around early flower.

Don’t sweat unless it’s progressing! Notice the difference between progressive deficiencies and sudden ones.

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swantip said:

Most helpful comment in this thread. Yes i had all of those things.Basically i didnt have a humidifier until day 25 or so.I used to spray with water with a sprayer to increase humidity.The problem is progressing though, slowly but steadily.I only just started giving it calmag.We'll see. Thank you for the response

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Nutty sKunK said:

How close is the light/ what wattage? And what hours are u giving her? 20/4?

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swantip said:

Now my 600w hps is about 20 inches far but it has been a lot closer before.18/6 hour schedule.I have light burn on top of the leaves because of the praying and fast stretching.I had to tie her down to keep this distance.It seems at least that the stretching has stopped(115cm high).Gorilla cookie from fastbuds,they sure grow like monsters for an autoflower.I had to innovate in my grow space to keep this distance.I also stopped my fan from oscilating now its blowing only on the lamp. I dont know how to correctly measure my rh though, it varies from 53% at the top to 60% at the bottom of my plant. I am going to experiment once and i decided to give her a bit more calmag from the biobizz suggestion of 1.2ml/L to 2.5ml and see what happens.I guess i have to live with this deficiency till the end, i just hope it wont affect the yield too much.

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