major ph issues, please help.

Discussion in 'Growing Marijuana Indoors' started by johnjohn, Sep 28, 2010.

  1. My 3 week old plants show minor signs of mag deficiency and slow growth, I figured that it is due to PH lockout. They originally got watered with poland spring ( aboutat 6.6 ph ) and then tap water which could have been even lower (added ph down and had a broken ph tester)...

    So today, over week later, I decided to give them water with higher ph to offset the low ph, I gave them a watering with 7.5ph. However, the run off was yellow and it tested at 5.5 ph.

    That just seems insane... i used a test strip and electronic ph tester and all seem under 6 for run off. But this is my 4th grow and honestly I always remember run off water to look yellow. Usually I don't test run off and just feed 6.8 ph to ffof soil, but this time my soil mix is:

    50% ffof
    30% roots organic
    10% perlite
    10% light warrior

    a couple questions:

    1. does your run off look yellow?
    2. should i flush them with 7.5 ph or higher until the run off hits 6.8?
    3. can the light warrior be lowering my ph so much that i need to always feed something like 8ph to get 6.8ph run off?

    any other suggestions?
  2. 1 - yes - unless im flushing..
    2 - IDK - depends on the your soil .. I need to hit it with a 3.1 to get a 6.8 runoff.
    3 - IDK

    My question is about your tap water..
    I hate tap water - mine comes from wells and has a high natural pH and PPM count.
    If I try to pH down that water I burn up a lot of acid just eating the Cal-Carb.
  3. my tap water is nothing special but i did successfully run 3 grows with it so I think it should be ok, it is usually between 6.8-8, most of the time it is about 7.5

    the last run-off was not really dark yellow but more light yellowish clear if that makes any sense, but still it did test out at about 6ph or below.

    your water is 3.1ph to get a run off at 6.8? that seems kinda crazy too....

    anyone else?
  4. Are you using the same soil?
    Have you thought about adding some Dolomite?
  5. I'm using this soil mix in each pot:

    50% ffof
    30% roots organic
    10% perlite
    10% light warrior

    I am not sure what Dolomite is and what it does, will it raise my ph?
  6. I usually use
    30% Top Soil
    30% Perlite
    30% Sand
    10% Vermiculite

    But then again - I'm basically a hydroponic kinda guy and I dont think of "dirt" as actually providing any nutes.

    Dolomite is concentrated limestone with a chunk of Mg tossed is.
    A great long term pH upper.
    A little bit goes a long way.

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