PH fluctuation in coco

[mesotropic]

Hi all, I'm growing some Martian Mean Green clones in coco slabs with drippers, using the Canna A/B ferts.



I always checked the PH of my solution, which came to about 7.8 after mixing the fertilizers, and lowered to about 6.0 every time since the beginning of this grow (which started about 40/45 days ago).
Problem being that I forgot to calibrate my cheap Hanna PH meter for about 3 months, and this morning after checking with the calibration solution it turns out it was really out of scale: it was reading 9.0 with the 7.0 cal. liquid.
That means that for this crop I always had the PH fucked up, but the plants didn't seem to suffer at all, probably thanks to the coco buffering qualities.

Anyway my question is: will the plants be shocked by the huge ph fluctuation are they gonna go through from this point on? Cause I set the PH to REAL 6.0 from today on.
Thanks a lot.

 

[Weedninja]

it was reading 9.0 with the 7.0 cal. liquid.

yikes! I'm not real familiar with coco, but with soil or hydro, I would recommend a change of no more than 3/10 of a point a week.

 

[Growdoc]

Get another typr of PH meter or ph paper to compare with, that way you know for sure what the PH is.

Now when you have a PH of 6.0 and you are sure, give it to the plants.

GrowDoc

 

[mesotropic]

Thanks for the replies guys. I just borrowed a different ph pen from a friend, and I re-calibrated mine. Now the solution is at 6.0... hope the plants are not gonna stress too much drifting from something like ph 4 to ph 6 all of a sudden.
It's crazy though how the plants did so well with such a low ph for a month!

 

[Raijin]

Coco does have great buffering qualities. You got lucky. You would have seen a pH burn on the leaves had it become an issue. That being said, Canna recommends a pH of 5.6 for coco only.