Calcium deficiency in high pressure aeroponics

[cage]

To deal with the question "do i give enough water", i read for other irrigation systems that 10% runoff is a good rule. Do you think its a good strategy in general to increase the watering so that i always match around 10% runoff? Thats what i tried to do.

And in conjunction with that how should i handle the salts, assuming that my salt data given/used is reliable, is it a good idea to also give 10% more or maybe give exactly as much as they consume?

I feel more and more confident that with the increase of watering from 2sec to 5sec and temporary even to 7-8sec, i overwatered/ still underwatered and maybe grossly overfeed, maybe especially during night as i have no automatic reduction of nightly spray times.

Here is my spray volume / flow calibration data. Only up to 5 sec but calculating for higher values should still give a good estimate. Keep in mind its two plants sharing that water. Roughly i can say they did use up all of the water up to 7sec during day time. For the salts i did not keep an eye. When i increased for the first time thats roughly when the problems started to appear.

The trigger was that i paniced when i saw parts of the roots drying out (due to the root system becoming so big that it blocks out certain areas). Also at that moment i did the first of two HOCL flushes, these i also consider as maybe problematic. Also at that time i had increased the PK booster from 25% initially (all was good then) to 50% and then to 100%, when i saw the possible PK deficiency signs like the purple petioles.

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I don't really have good suggestions for how to adjust the aerosystems.
The 10% runoff is usually good for flushing the little that has accumulated and resetting nutrients for the rest of the medium.
So you have a bit of a margin to have too little or bit too much nutrients.

The petioles turning red (at around 2-4weeks of flower?) is probably the P deficiency,
since that is the time she starts to use some more of it.
Few reasons for it to happen is the low temps or it could be because of the slight root problems which might have
interfered with nutrient uptake. I'm still leaning for the low temp issue.

 

[endorflight]

Sorry for the late reply. With the heatmat installed and +1 degree celsius on the night temps, the root temps where now between 17.5 and 18.5 degree celsius for the last nights. The symptoms have progressed.

I realized that the symptoms with the rusty veins affect only the left plant. This is now very apparent. The plants are the same strain but grown from seeds. The left plant had also shown rusty spots very early on so could this be a genetic thing? I attached a baby pic of her. The last picture is a closeup of the right plant for comparision. That one does not show that symptom at all!

The symptoms with the curled up and little burned leaf edges affect both. However i recently looked at the new product pictures of the RQS F1 seeds and i see very similar symptoms on supposed to be perfect plants/pictures, so it might be not that unusual for late stage plants if its not getting worse?

In general could it also be that these plants are ahead of their schedule? They are now at flower week 6.7 of the breeders recommended 8-9 weeks.

The petioles turning red (at around 2-4weeks of flower?) is probably the P deficiency,

Yes i think i noticed it first around week 3-4, however any attempt to give more PK or higher EC resulted in the EC rising and did not reduce the purple color that i would notice. Only around 1.0 EC the salts are absorbed equally with the water.

 

[cage]

Different seeds can always have quite a bit variance since they have different genetics.
Depends on how stabilized the genetics are, but always some differences.

The more affected plant look like it's taller?
Maybe some light excess?

Not sure how much you were giving light during 2-6weeks,
but every stress factor reduces the amount the plant can handle.
So some low temps, with few root issues and if the light wasn't dialed down during these, it probably has been bit much.

Stressed plants often finish bit early, since their focus shifts to getting some seeds done, instead of maximizing the amounts of seeds aswell (read buds). Some of it might be just normal variance in flower time.
This late in the flower I'd really go easy with the light and focus on letting the plant finish its thing without pushing her too hard.
Like 800ppfd to have plenty of light still, but doesn't push her too hard if she is not 100%.