COCO COIR How to right the runoff ship: pH/PPM Going In -> pH/PPM Coming Out

[rangerjake]

I previously had an issue with very hard water and starting PPM being near 300 before nutes. This has been resolved using a combo of a different water source (90ppm) and rainwater (+/- 10ppm).

Over the past few days I have been diligent about checking my input pH and PPM and am trying to deal with some of the potential issues I am seeing.

First and foremost, the plants look fine. Happy healthy and no above surface indications of issues. This is good.

Here are results of feedings for my few plants over the past few days, each day is color coded:


Raspberry Cough: Day 27 of 75ish day Veg

Day 1--- H2O @ 90ppm Day 2 --- H2O @ 75ppm Day 3 --- H2O @ 100ppm

Going In: 6.2pH 790ppm Going In: 6.0pH 774ppm Going In: 5.4pH 880ppm
Coming Out: 6.4pH 897ppm no measure taken on runoff Coming Out: 6.4pH 875ppm

Blue Mystic: Day 27 of 75ish day Veg

Going In: 6.2pH 790ppm Going In: (1/2 strength feeding) 5.6pH 480ppm Going In: 5.3pH 100ppm w/out added nutes
Coming Out: 7.2pH 1775ppm Coming Out: 7.0pH 1700ppm Coming Out: 7.0 2000ppm

WW Autos: Day 27 (week 1 of flower)

5.9pH 535ppm Going In: 5.4pH 640ppm
Coming Out: 7.0pH 1430ppm Coming Out: 6.7pH 1116ppm


My analysis of the above is that Raspberry is doing very well. Those numbers seem spot on.

The WW Autos are a bit higher pH and PPM than ideal but the smaller containers (4gal of coco/perlite) are easier to correct and lower pH feedings succeeded in making a drop only 24 hrs later.

Blue Mystic is the most concerning for a few reasons. The obvious numbers indicate that it has the highest retained salts. The larger container (about 8gal coco/perlite) seems more stubborn to correct. Furthermore, the fabric pot has some white staining on the bottom couple inches of the sides which to me is indicating retained salts. Also the container seems to be holding much more water than the Raspberry which is the same quantity and mix of medium. On the Day 3 feeding the thing was still like a saturated sponge on the bottom half. That, to me, was very concerning.

I decided to not water/fertigate today. I think the thriving plants will not be overly stressed by a day off, and I want to give the Blue Mystic a day to drink or release the retained water.


I am interested in any thoughts people have about the best way to get Blue Mystic to the numbers of Raspberry. Half strength fertigation at low pH? A full flush? Any other thoughts about this data is helpful too.

[rangerjake]

[Mr.furley]

I have never had a problem with running plain, ph'ed water in one go, gallon after gallon, back to back to drop the ppms and raise/lower the PH till it is stable.

it does not completely remove all the salt buildup so you should look into something like sledgehammer two to three times during a grow.

[HappyDaze]

rangerjake I've been watching some of the threads started by GWE people going through growing pains using coco and other soilless media with great interest. I went here to learn a little more about coco. https://www.cocoforcannabis.com/ Their suggestion is to use a higher percentage of perlite in your mix as your container size increases. I see why based on your experience; bigger pots apparently don't drain as well. They suggest a 50/50 mix in pots bigger than 5 gallon. Your record keeping and analytical approach is great, thanks for sharing....What proportion of perlite/coco have you got going now and is it the same in all your pots?

Mr.furley When you start new pots, do you rinse and condition your coco, or do you use pre buffered coco straight from the brick/bag, and does it matter which brand you choose? Also, I've read that it's important to rinse the fine stuff out when you start. How exactly does the rinse work? Do you rinse through a screen to eliminate fine particles or does high quality coco come cleaned and read to use? Thanks.

[Mr.furley]

rangerjake
You are correct they are soooooooo many factors and they very from so many other factors, there is not one correct way of doing it right 100% of the time, something can easily be a miss especially with multiple strains.
I believe that knowledge is power and the more you try the better grasp you have on things, I do encourage trying new things.

HappyDaze
You have not offended in anyway, it is my own personal feelings in the matter that have got the best of me today and I have never laid it down on here publicly.

[Mr.furley]

Also thought to mention rangerjake
Doesn't the "Doctor" strongly discouraged checking runoff As it can create problems you don't have?

[rangerjake]

@Mr.furly I think the doc is a big proponent of measuring runoff EC early and often