Soil Ph - Help Please

Discussion in 'Growing Marijuana Indoors' started by girlsgrow2, May 19, 2013.

  1. I have never really tested the PH of my water or soil, but I wanted to get a bit more good stuff into my soil mix, so I bought a Ph tester.

    When I first tested the water coming out of my well, it was a little bit high (depending on who you ask), but the nutrients lowered it right down to where it needed to be, so I didn't mess with trying to raise or lower it.

    However, I started making some mixes so I could test the ph and make sure that I wasn't gonna kill my babies when I put them into it and I'm running into some weirdness. I'm wondering if my ph monitor could be broken? I've only used it about 4 times, could it need to be calibrated already? If so, I think that that normal?

    My well water is ph'ing at 7.4 now, which is way higher than it was before. And I tested some distilled water (which should be neutral, 7.0 from what research I've done) and it's coming up at like 5.5 or so.

    I made a mix that was 2 parts moss, 2 parts potting mix, 3 parts perlite and 1 part compost. The run off came out at 5.5, which would have meant that the ph of the soil is 3.6. SUPER low. So I threw one more part compost into it to see what would happen and the run off came out at 6.5, which would put the soil at 5.6. Those calculations are correct, right?

    If not, I need to add something more until I get the ph of the soil up a little bit still by adding or subtracting something, right? Or should I raise the ph of the water to start with?
    Sorry if I wasn't clear enough, hopefully I explained that properly. I'm just worried about burning my plants when I move them to 1 gallon pots for vegging with this new soil mix. I used to just use a potting soil mix and perlite, that's it. I'm adding the moss and compost to the deal to see if my babies can be even better than they are now (which is pretty darn good, finally!)
    Thanks in advance to anyone who answers me!
  2. i dont know about your calculations but in the meantime you should pick up one of those cheap ph test kits for fish tanks and use that its not accurate to the tenth but it does go in .5 increments and the color code is on the bottle of tester stuff that comes with it.
  3. Adding about 1/2 cup of lime per 5 gallons of soil mix will help buffer the Ph of your soil closer to 7.
  4. Dang, I ALMOST got some lime yesterday when I picked up the moss and perlite. I'll go back and grab some when I go get a ph calibration fluid so I can test my meter. Thanks for the suggestion!
  5. u want ur runoff to be 6.5. ur runoff is the most critical measurement. it is the actual ph of ur root zone. if ur runoff is stable at 6.5-7 u r good to grow.
  6. If your tester is one of those "probe" types that you stick the metal spikes in the soil THROW IT AWAY!
    Those are incredibly inaccurate.

    If its an actual pen type then it likely just needs calibration.
  7. my last PH pen was a cheap £10 off eBay and it worked perfectly for 8 years before it needed adjusting.... and then I killed it in the process lol. but I tested it every now and then and it was spot on

    I'm not sure how your calculating it but if you pour 7.0 in to the soil and test a small amount of run off and if it's say 6.0 it means the soil was at about 5.0 ish, but now it would be closer to 6.0 anyway.
    testing soil PH does involve a little guessing. your better off always making sure the nutrient solution is exactly where you want the soil to be and sloshing plenty in there and let plenty run out and discard it. not flushing the soil allows nutes to build up in the soil and that will cause your PH to go way off

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