Nutrient steal

How early will you start to see nutrient steal as you approach harvest time? I have plants (yes, grown in coco) that are starting to display what appears to be Ca++ deficiency. I have compensated with a little extra calcium and increased fertigation to no avail. They are about three weeks out from breeders estimated harvest time. I am unsure if is possible light burn (not thinking so), actual refractory Ca++ deficiency or if it is the start of nutrient steal towards the end of plant life. Is three weeks too early to witness this phenomenon?

Excess potassium can appear as a cal / mag def. From experience, in coco.

Ahhh... okay. Something I hadn’t considered! Now, as a noob, let me ask this: how does the excess potassium come about? I understand that K+ is the most in-demand element for cannabis during the flowering stage. I believe my only source of K+ is from AN Coco Bloom nutrient solution. I hadn’t even been using a Bloom booster until two days ago when I finally scrapped up enough money for some Jacks. I have had this spotting going on for about ten days now. I definitely appreciate the info.

yeah never understoof the "coco need more calmag" thing.
its usually precharged and flushed by ourself few times before use .. so its charged with the good cations
then i water it like rockwool . i also used coco specific nutrient in the past (canna) but not sure its needed .. if used with ro just be sure to use a soft water regimen .

MountainMedic1206 said:

Ahhh... okay. Something I hadn’t considered! Now, as a noob, let me ask this: how does the excess potassium come about? I understand that K+ is the most in-demand element for cannabis during the flowering stage. I believe my only source of K+ is from AN Coco Bloom nutrient solution. I hadn’t even been using a Bloom booster until two days ago when I finally scrapped up enough money for some Jacks. I have had this spotting going on for about ten days now. I definitely appreciate the info.

Click to expand...

A few ways I know of...
Coco naturally has K in it.
Salts in the coco, over time building up, including K. (drying out, heavy feedings. for example)
Feeding improperly, not enough runoff, not feeding often enuff.

A couple good coco reads. They explain much better than I.


"The CEC of coco is naturally loaded with potassium (K) and sodium (Na), with little or no calcium (Ca) or magnesium (Mg). These are the four cations that are most important when buffering coco."

Also I have to remember: Coco fibers break down over time, during the grow. Resulting in new cation sites being exposed. The newly exposed sites suck up some of the available CA and/or MG from the nute solution. Plant and coco are competing for the CA/MG. (I assume some K and NA are also exposed during the break down process....and made available to the plant.)

Man, I sure appreciate you. That gives me something to work on. Thanks again!!!