Measuring the pH of the run off sounds dumb.

Seems to me like the layers of soil will act like a giant chromatography tube and pick up or drop all sorts of things

it would also depend on how much water you add... if you have a lot of run off then it will dilute the solution and if u add too little it will be more concentrated

yeah I dont get this method either and I've been growing for a while now..it makes no sense to me... I think people just post random things on here that they read on other websites..
personally I am a trial and error type of grower.. if it doesn't work then I dont do it again, but if it does work then I just keep on learning for next round.

Although I suppose it would give you a rough idea of what your soils PH values are at I do not think that it would be totally accurate. (just my thoughts)


Peace and Happy Growing

pH is only defined for aqueous solutions.

So dust dry soil does not, by definition, possess a pH. Only moist soil has a pH, and when you measure it you are measuring the pH of the water that the soil has absorbed.

So the pH of runoff, which is a generally accepted indicator, would appear to be OK.

Its a rough estimate, how hard is that to understand? If your run off says the ph is 7 or higher than its obvious that your ph is too high. Lower than 6 for the most part its too low, some stains like it around 5.8. Lets you know if you need to make any adjustments. To get a more accurate reading get a soil ph meter. I understand where your coming from Spanishfly, but when does anyone have a plant in dust dry soil?

here is some real science instead of stoned conjecture.
http://www.ph-meter.info/pH-measurements-other-procedures

Spanishfly said:

pH is only defined for aqueous solutions.

So dust dry soil does not, by definition, possess a pH. Only moist soil has a pH, and when you measure it you are measuring the pH of the water that the soil has absorbed.

So the pH of runoff, which is a generally accepted indicator, would appear to be OK.

Click to expand...

aqueous solutions as opposed to what?

so if i test the ph before i feed and its says 8 and then i feed it and its 6.5 what does that mean that it's perfect or too high? thanks

kraftsmen559 said:

so if i test the ph before i feed and its says 8 and then i feed it and its 6.5 what does that mean that it's perfect or too high? thanks

Click to expand...

shouldnt be feeding MJ plants with 8.0 PH to start with....if your ph is jacked just flush with correct PH'ed water tell the run off reads the same PH as your putting in..

when the run off is lower then what your putting in you probly have alot of salt bulid up (from nutes)..should keep flushing tell it reads what you want.

you may think its dumb to do this but it helps keeps the plants growing to there max efficienty .