Discussion in 'First Time Marijuana Growers' started by cvcs1, Aug 6, 2011.

  1. Hey Guys!

    Can I use tap water for my plants? And if theres bad about using tap does letting it sit out for 3 days fix this?

    Thanks!! :smoke:
  2. outdoors or indoors?

  3. If th PH of your water is ok then yes. (test it). Mine is a perfect 6.4 PH (SOIL GROW). You dont need to leave it sitting out for days. If its room temp then its good to go as cold water will shock the roots.

  4. It does not matter.
  5. Everybody's tap water is different, there's no way anyone from here can tell you if yours is OK or not.

    Put a good filter on your tap water and then you should be fine. If you filter it then chlorine is among the things already removed, but if you don't filter it then at least let it sit out 24 hours so the chlorine can evaporate. And no matter what, agree to give it to your plants at room temp.

    BTW there really is no such thing as the perfect pH for the input water, the key is the pH of the runoff. So yes while MJ likes a pH of 6.4-6.8, if your runoff is out of that range then you should buffer your input water regardless of where it starts out. The runoff pH reflects what your roots are actually experiencing, and that pH is the interaction of your water, nutes, and soil mix.

  6. The run off will always show a much lower PH than the actual soil's PH. Dont waste your time testing the run off as its deceiving. The PH of the soil is what you should be testing about 4-6hrs after watering with a good probe. I dont even chech my PH anymore. I stopped that years a go.
  7. So basically.. if the average ph of my tap water is in the middle, and i filter the water + put it in at room temp I should be great?

    Thanks for all the replies!!!

    Oh and twista, you have 420 posts lol.
  8. doesn't PPM have something to do with the pH?
  9. The water from my tap is 350ish PPM at a PH of 7.5.

    It's fine. Check my sig for results.
  10. whats ppm?
  11. Parts per million.

    "This is a way of expressing very dilute concentrations of substances. Just as per cent means out of a hundred, so parts per million or ppm means out of a million. Usually describes the concentration of something in water or soil. One ppm is equivalent to 1 milligram of something per liter of water (mg/l) or 1 milligram of something per kilogram soil (mg/kg)."
  12. so what does ppm have to do with my mj being healthy
  13. It tells you the concentration of chemicals other than h2o that are in your water. Depending on area, some tap water will have large amounts of chlorine or other minerals that can have an effect on the overall growth of your plant. For example, city water will typically have chlorine, and at least fluorine added to it, as well different municipalities can have water that varies widely in ph. Well water on the other hand, will be lacking in chlorine and fluorine, but tends to have heavy mineral deposits and low ph from my experience.
  14. #14 KittyInACup619, Aug 6, 2011
    Last edited by a moderator: Mar 15, 2016
    exactly. city water has so much shit in it, the ppm is through the roof. if you don't have a good enough pH meter, all you can really do is get the pH, throw more chemicals in the water to get the pH down which only raises the ppm, and you're plant is drinking everything that is in it. if you don't purify or filter your water, shits gonna get hectic, brah.
  15. Never heard that. The consistent advice from many, many skilled and experienced growers is to test the runoff. The runoff essentially is the water in the soil, just before it runs out. So why would the runoff be different from the water in the soil? A probe can't actually test the pH of a solid like the soil, rather it tests the pH of the water in the soil.

    I hardly ever check myself -- once you have a good setup dialed in, if you use the same soil and same nutes and same water then you should have pretty much the same pH, and once you know if that needs to be buffered then you can continue to do that without having to test it all the time. My pH drifts a little high so I add a little PHDown each time. I test occasionally to make sure I am still on target, it always is.

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