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Nutrient pH - Variation of feeds to spread compound uptake

Hi all,


running Coco, I usually feed with a consistent pH of 5.9. Doing some studies into Nitrogen and it's major component chlorophyll I came across some range charts. I've previously seen people use Cal Mg with Coco, this would tell me I'm dropping both to potentially zero on feeds.


With this in mind, I noticed a 5.9 pH feed actually prohibits the absorption of other compounds. Would it be good practice to range the feeds at 5.9 then 6.5 (progress or at the very least repeatably) to ensure the full range is taken?


Any experience on this welcome.





Edited by Owderb
Remove links and pics to another weed site

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Cal-mag is only really needed if your background ec is 0.4 or less. When in coco,I start my seedlings at a ph 5.8ish. When they start to get a few leaves on them I set my res at ph 5.6,and then let that rise over the course of the week to 6.2/6.3,and bring it down if necessary with ph down. At that range they can absorb it all.

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Your chart is a little different from the ones I have.


Mine (converted to text form) say


Nute LockOut PH Ranges
(N) - 4.5-5.0
(P) - 6.0-8.5
(K) - 4.0-4.5, 6.0-6.5
(Mg) - 2.0-5.7
(Ca) - 2.0-5.3
(Zn) - 5.7-8.5
(Fe) - 2.0-3.5
(S) - 2.0-5.5
(Mn) - 2.0-4.5
(B) - 2.0-5.0
(Cu) - 6.5-9.0
(Mo) - 2.0-5.5


As you can see, some major lockouts happen at a PH of 6.0 (P, K) and these elements have limited availability at a PH of 5.9+, Mg needs 5.7+ but the availability of calcium is limited (but not locked out) over 5.8. Personally, I would run between 5.55 (only every now and then) and just slightly over 5.8 (most of the time) so you keep in the range of no lockouts except Zinc, which is obtained every now and then with a drop to 5.55. Zinc is not a mobile element so you do not need to worry about older leaves suffering from sporadic availability.




And to help diagnose which elements are lacking/locked out from leaf examination




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Thanks @MicroDoser , sound advice. I'll go with the 5.55 as you say every now and then, keeping to my usual around 5.9 typically.


Thanks man!

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