Runoff Water and Soil pH Info-How to use it

Discussion in 'Growing Marijuana Indoors' started by bonghitz420, Feb 2, 2010.

  1. #1 bonghitz420, Feb 2, 2010
    Last edited by a moderator: Feb 2, 2010
    OK so I'm asking this question because I haven't found a clear answer on this subject and maybe mine is a little out of the ordinary.So I have 3 beautiful girls 11 days into flowering.I just gave them their watering @ 2L of 6.3pH water per plant...all in 5 gallon bags.As of late I have really been keeping up on them and one thing in particular is that my runoff water,and its the very first runoff water so I know it's the most accurate reading,and the pen that reads it is also perfectly calibrated,differ from my soil pH tester reading.Is this normal or is my soil pH tester faulty?For example one plant's runoff is 6.0 but the soil tester says 6.8?I've been running a steady solution and watering of 6.3If not can I use this information to judge how much "food" is in the soil.I've never heard of this before but the Advanced Nutrients rep told me if the runoff pH is less than the water pH you just put in you still have enough food in the soil.So it's basically a 2 part question.Any info would be really helpful!Thanks guys!
  2. What kind of soil ph tester are you using?

    If it's one of those cheapo rods with a dial on the top, it probably isn't worth paying attention to..

    Otherwise, after watering, think of the soil Ph as being a mix of the water's Ph and the runoff Ph, so it's bound to be somewhere in between.
  3. Yea it's one of those cheapp rods from lowes so u think it may be unreliable?should I just go by the ph of my runoff?I always ph my water n nute solution so I guess I be aight
  4. I have one of those rods too. I just use it to stir up soil. It's a complete waste of money as a Ph tester. I once had it sitting in soil, which I knew to be very acidic, for 2 hours and the needle did not move at all. Similar accounts can be found all over this board and the rest of the internet (aside from the manufacturer's site, hah).

    Invest in a better soil tester if you got the cash, otherwise focus on the runoff and the water you put into it.
  5. Ya i have one of those cheap ass Lowes testers too. They're totally unreliable. But it is normal for your runoff pH and your soil pH to be different from each other, because the actual soil itself doesn't change pH, just the moisture in it. All the Lowe's/Home Depot soils have a pretty high pH. Thats why you should use Fox Farm Ocean Forrest soil or something similar.

    The important pH reading to worry about is the pH of the water you're giving them. As long as it is in the right range you shouldn't have to worry, as long as the soil remains moist (which it always should be of course).

    This is just what I have learned from experience so don't quote me on this lol:)
  6. #6 dragonsfire1988, Feb 3, 2010
    Last edited by a moderator: Feb 3, 2010

    Soil should not always be moist. That would promote mold and root rot. The soil has to dry out between waterings, otherwise you risk, like I said, mold or even worse overwatering. Also the plant wouldn't have time between waterings to absorb everything from the previous watering.

    You are correct in saying that it is most important to worry about the Ph of the water you give the plants. I have found this to be most true, as my runoff is consistently 5.5, but the plants are healthy as hell with 6.5-7 water going in. Runoff IS all about the soil, though, as some soils are more acidic/alkaline than others...the soil definitely affects the runoff.
  7. Ok I am having a similar issue. The water I am putting in is at 6.0 -6.4 the runoff is anywhere from 4.5-5.0. Are you saying thats not a problem? I am using Foxfarms Ocean Forest and in flower Tiger Bloom.

  8. water going in should be at 6.5-7.0. Runoff is "acceptable" at 5.5 (no lower), based on my experience and nutrient availability.

    6.5 is preferable all around.

    FFOF is Ph balanced at 6.8 out of the bag, so you might be having issues with the nutrients you put in (nutrients tend to lower soil and water Ph).
  9. Ok well I was just thinking, it might be because I just flushed becauase I had a PH issue. I tested the runoff of the flush. I am hoping that it was just all the deposits that had been building up. FFOF is typically between 6.3 - 6.8 so if the water I am putting in is around there I should be fine. Thanks
  10. Well man the tech from advanced nutes says that if you water @ test the runoff and it comes out way low like yours is,the tech says that there is still enough food in the soil for your plants.I have no idea if this is true.I am using ocean forest as well.Advanced Nutes says pH your soil to 6.3...maybe in your case you better flush man...your plants are in an acid bath
  11. #11 bonghitz420, Feb 3, 2010
    Last edited by a moderator: Feb 3, 2010

    Damn the bags I just got from the sto' their pH was above 7!?Yikes!Yet again,my soil tester is a POS but on the other hand a fem lemon skunk seed,2 of em,sprouted and yellowed and died for no reason leaving me to believe it was the pH or maybe hotspots in the new technique is to take that entire bag of FFOF and flush the livin hell out of it to get it down to atleast 6.5...7 is to high MJ likes slightly acidic soil
  12. Maybe this thread would be "sticky" worthy....
  13. You should never let your soil dry out all the way, that would cause your plants to stop growing and wilt:eek:. Once the top INCH of soil is dry, it is time to re-water. You are right, the plant doesn't have time to absorb all the nutrients between waterings, but that is why you alternate every other watering between nutes and plain water.

    You dont want the soil to be completely saturated (muddy consistancy). This is what is considered overwatering and will cause mold and root rot. But you do want the soil to remain consistantly moist. About as moist as it was when you picked it up at the store. As long as you let the top inch get dry between waterings you shouldn't have any root rot or mold issues (unless your humidity is too high)

    George Cervantes says to keep the soil consistantly moist, so thats what i do and I've never had any problems. Cheers
  14. Aye, that's what I was tryin to get at. Thanks for clarifying. I was mostly trying to point out that the soil should not always be soggy and saturated (which is what your earlier statement made me think)
  15. OK we all know not to overwater but I haven't had the time to research the fact that when you pour water through the pots/bags and the pH comes out lower than what you put in there is still nutes in the soil...ne1 figure this out yet?That is not the case in my situation,yet,but it would be helpful to know if the info he gave me was correct

  16. Yea man I just shove a finger in the soil up to my first knuckle..if its dry I water.I've learned my lesson on that a few grows ago lol..From the words of Urban Grower "If it ain't dry,don't apply"
  17. There could still be nutes in the soil. Or the soil is just acidic to begin with - some soils contain ingredients that are naturally acidic and bring the Ph down (lime, for instance). It all depends on that particular soil and what exactly you've added to it and how recently.

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