Pour-thru test

Billy25

Billy25

Member
I am curious about the results I get doing a pour-through test of pH and EC. I read a publication by Purdue University agricultural extension that described the process of soaking the media in water, letting it stand an hour, then pouring more water through and catching what drains out of the growing media. That water is then tested.
The pH was what I expected. The tap water used here has a pH of 8.1, and the pour-thru water had a pH of 5.5.
The EC was off the charts. Our tap water EC is .90, and the pour-thru read 8.9!
Since the plant (a flower) was sick, I assumed it had been way over-fed nutrients.
So, I repeated the process on a very healthy Northern Lights in vegetation. Same results.

The media is Sungro Mix #4 which is peat, vermiculite, silica.
The nutes are Jack's Professional which I mix to an EC of 1.9 with tap water and add some pH down.

Any idea why the crazy EC numbers on the pour-thru? Does Peat Moss do that?
 
Billy25

Billy25

Member
Ok, nobody? ..............
May have answered the issue myself.
Put some new media, fresh out of the bag in a solo cup, rinsed a couple times, then captured the runoff.
Here's what I got:
RO water: 32 ppm
runoff water >800 ppm
Maybe N6 on the Nitrogen?
 

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twentyeight.threefive

twentyeight.threefive

Well-Known Member
Billy25 said:
I am curious about the results I get doing a pour-through test of pH and EC. I read a publication by Purdue University agricultural extension that described the process of soaking the media in water, letting it stand an hour, then pouring more water through and catching what drains out of the growing media. That water is then tested.
The pH was what I expected. The tap water used here has a pH of 8.1, and the pour-thru water had a pH of 5.5.
The EC was off the charts. Our tap water EC is .90, and the pour-thru read 8.9!
Since the plant (a flower) was sick, I assumed it had been way over-fed nutrients.
So, I repeated the process on a very healthy Northern Lights in vegetation. Same results.

The media is Sungro Mix #4 which is peat, vermiculite, silica.
The nutes are Jack's Professional which I mix to an EC of 1.9 with tap water and add some pH down.

Any idea why the crazy EC numbers on the pour-thru? Does Peat Moss do that?
Click to expand...
What meter do you even have that measures 8.9 EC?
 
Billy25

Billy25

Member
Boatguy said:
There are quite a few other things in that soil besides peat moss. That kind of test would only work in something more inert
Click to expand...
True. Microbes and vermiculite, with assorted sticks and other material I imagine was dredged up with the peat.
Not even sure I believe the Nitrogen test because I have a very happy Northern Lights growing in the stuff. The flowers that died were celosias, if that matters.
 
calvin.m16

calvin.m16

Well-Known Member
Runoff is only a rough idea of what is going on in the rootzone in my experience, I will use it sometimes to gauge if I need to give plain water or not in coco, usually once a week I give plain water to prevent issues. I don't "FLUSH" I just give them plain water when I see the runoff EC in the trays is above ~3 EC. IF you want to know what is happening in the actual rootzone look into a BlueLab Pulse meter that stabs directly into the rootzone and measures EC, Temp & Moisture.
 
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