Ph Modification Question

Discussion in 'First Time Marijuana Growers' started by Singoe, Sep 21, 2009.

  1. Im using miracle gro potting mix for my first grow, which has a ph of 5.1. The ph of my tap water is 7.2 so i need to get that up by .2 for the first few watering and then lower it. My question is whats the measurements for changing the ph? Like 2 tablespoons of vinegar in 4 quarts of water at 7.2ph will change it by how much? Same thing with baking soda.

    And id rather do this than go all over town trying to find ph up and down.
  2. Well, Walmart sells pH up and pH down in their pets section for about $4? All pet / fish stores should carry pH up and pH down. I remember reading about using vinegar and baking soda as replacements for pH up/down but I recall something along the lines of nutrient lockout when you use those.
  3. U saved my life! haha i was actually going to go to walmart for vinegar and baking soda and like measurement spoons and stuff then I asked myself "hmm i wonder if theyd have ph up and down... NAH!" Thanks so much +rep
  4. pretty sure you shouldnt use aquarium ph up and down. might want a second opinion though.
  5. I dont think there is a differance it wouldnt make much sence at all if they were different
  6. wait its walmart?! shouldnt they also have a gardening section? that would have ph up and down? haha
  7. I never seen pH up or Down in the gardening section, just in the aquarium section. However, you have to remember that many aquariums carry live plants, as well.

    I've googled and googled and I've read reports that it works fine, and other reports where people had a 'bad grow' due to 'most likely using aquarium ph up/down'.


    I went ahead and checked the contents of API pH Down (Which is the product walmart carries, I believe) and its <10% Sulfuric Acid.

    It also states on their website its safe for live plants.

  8. Id give you a hug but im over here haha thanks man. if it wasnt for you i prolly would have killed my plant haha
  9. they also carry it in the section for pools...
    In big blue bottles.
  10. hey dude if ur tap water ph is 7.2 u want to lower it soil grows ph needs to be under 7, i think its between 6.7 - 7.0 is ideal cant remember off the top of my head could be wrong
  11. His soil has a low pH so he is trying to balance it out with a higher pH water.
  12. Did you find that your soil had a PH of 5.0 by testing runoff, or the soil itself?

    Do you have to test the H20 and your H20/Nute combo seperately? They might both have different PH right?

    Does anyone know the ideal range's?
  13. Not sure about the soil question, but for the nutes/water question it depends. If you are just watering with h20 alone, check and adjust the pH of the water. If you are using nutes, then add the nutes, test the pH and adjust accordingly.

    Ideal pH for soil grows is 6.5.
  14. Thanks ! Plus rep:smoke:
  15. im pretty sure the aquarium ph up/down is what gave me all the problems in my first grow. the only thing ive changed from my first grow is aquarium to hydroponics ph up/down and this time around im having great sucess with virtually no problems. but thats just me maybe youll have better luck. gl
  16. What brand of aquarium pH up/down were you using?

  17. Depending on what stage of the grow you are in, will depend on what pH to keep the soil/nutrients.

    If you don't want to do this, it is best to keep the nutrient solution at pH6.5 throughout your grow.

    The run-off should be alot lower than the solution you add to the soil (run-off should be between pH5.8 and pH6).
    When soil drys out, the water evaporates (other than what the roots take up), the nutrients can't evaporate, so whatever nutrients that the plant doesn't use, will be left in the soil. When the nutrients become concentrated, they become acidic, lowering the pH of your soil. Other than letting the soil dry out to let oxygen to the roots, it is important to let the soil dry out to lower the pH of the nutrients, so as to let the plant take up whichever nutrient they need at a certain pH level.

    People wonder why Hydro pH level is lower (usually pH5.8) than soil (pH6.5), this is because if you add the nutrients to the soil at pH5.8, when the soil dries out, the soil will become that acidic it will cause nute lock and kill your plant.

    I feed my soil plants nutrients every other watering, i give them plain water one watering, and then add nutrients the next time. This helps having pH problem and nute burn.
    I don't flush come harvest time either, my soil wouldn't be full of disolved salts from the nutrients.
  18. im not exactly sure. it was from a local fish store so probally a common brand. im not saying that this was for sure the reason for all my problems but this is the only variable that has changed from my last grow and i havent had any of the problems that i had last time. so im just guessing that this was the reason for my problems. could be wrong though. id say just buy some from your local hydro store. there is not much of a price difference, and at least then you could have peace of mind. just my opinion though. gl
  19. walmart didnt have anything exept for a ph test kit and it sucks. But i found a hydroponic store close to home so its no problem im going there tomorow.
  20. Do NOT use baking soda - lots of sodium, which is toxic to MJ. Keep to the aquarist stuff, if you can get nothing else.

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