Testing pH question

Discussion in 'Growing Marijuana Indoors' started by HighOnTheHill, May 28, 2009.

  1. #1 HighOnTheHill, May 28, 2009
    Last edited by a moderator: May 28, 2009
    When I measure my pH by sticking the meter in the soil its really difficult to do because the meter goes all over the place. I don't think its as reliable as it should be given it was a $45 meter. I've got some plants reading 6.5-7, and some reading off the fucking charts @ 1-3. Same soil, same nutrients and feeding regime. It's gotta be bullshit. I'll post some pics up for an example here in a few.

    So I've got the meter sitting in a cup of my nutrient mix, and its reading a tad bit under 7.


    So my question is, would measuring the pH of the water be a fair substitute for measuring the pH of the soil? There CAN'T be that big a difference between plants planted in the same medium with the same shit going into the medium.

    Edit:

    Okay so, I just tested the pH again, and I might have spoke too soon. I just gotta find the "right spot" to test the pH in. Seems all of them are between 6.5 and 7 so I'm good. But as an example of what I mean, these are both pH readings from the same plant.

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  2. Read the instructions with the meter carefully. I think you have to soak the soil with absolutely pure water (maybe deionized) PH 7, and then tst for three or four minutes before taking a reading. The probes have to be dead clean also. I went to a liquid probe for the nutrient solution, the meter is not accurate in solution. Its calibrated to soil resistance.
    Greenfrog
     
  3. Right on man. I found that a little patience helps. I actually threw the package away, but all it said was about cleaning a specific (one on the right) probe with an included scratch pad (just a brillo pad). The soil is supposed to be moist, but it didn't mention anything about the type or quality of water.

    Either way, when its in certain spots, It'll sit @ pH of 3 for 5 minutes, then others it'll read right.

    Still wish I could just measure the water though.
     
  4. I know this is a stupid question to ask ( and yes your entitled to give me a stupid answer ;) )

    is the switch set to pH ? looks like fert setting to me

    and that beast will measure the pH of your soil..not your h2o solution. and yes the readings will be all over the place in h20.

    PS don't trust the moisture setting on that thing for MJ growing.
     
  5. Yeah I noticed that too, but it's set on pH. I actually had to go back to check right after I posted the pictures. Not really sure why I bought it because the only thing that I see that I actually use is the pH meter. Not so sure I'd trust the "Fertility" meter at all.

    Moisture apparently isn't measured well with those either :p I just sorta use that as a GENERAL idea of how moist the soil is.
     

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