Question on sequence - PH, watering, PH correction

Discussion in 'First Time Marijuana Growers' started by Foyle, Aug 12, 2011.

  1. Hi,

    Curious as to whether, in the case of adjusting PH, one first waters with uncorrected water - call it water measured in the low 5 PH - meter the runoff out of the pot, and from that measurement correct the water for the next watering?

    Example: uncorrected water gets a PH reading after pot flow through in the low/high range - then the next step is to adjust that water up or down appropriately for the next watering?


    Correct the water first up into say, the high 6 neighborhood, water, meter runoff, and THEN readjust the water whichever way for the next watering?

    From what I've been reading, it seems that the idea is to get the uncorrected runoff first and adjust the water accordingly for the next watering but I wanted to check to see if I'm misinterpreting.

    Also, I've scoured this site for baking soda proportions per gallon for raising PH but all I've seen are things like "just a pinch" or "very little." Anyone have some insight and some experience with amount values on this?

    Finally, lime - mix with water (towards adjusting its PH up) or top dress, water with corrected or uncorrected water, measure PH, and adjust accordingly?

  2. You always want to test before adjusting anything. If you dont then you have no real idea on what adjustments are needed and can cause more harm than good.

    Baking soda, I cant tell you the proper amount but I can tell you from experience that a whole lot is not the answer. Made that mistake once before and damn near killed every one of my regular plants (not mj). I still have major damage from that incident, but luckily the plants recovered and the new growth is excellent.
  3. Thanks!

    Okay - to make it more interesting - I used my brain and figured out what you told me - water first, unaltered, check runoff - go from there.

    This, I did.

    The particulars:

    Water - PH 5.15 (Municipal water left outside for five or so days.
    Dirt: MG Organic
    Plants: One month old, give or take a day or two.
    Health: Healthy, green, some small signs of calcium deficiency on some of the older leaves. Continuously churning out new leaves from the cola points
    Height: About 8" to a foot, more or less.
    Pedigree: Bagseed - looks more indica than sativa
    Additions: Molasses - 2 tbs/gallon, powdered cocoa (don't laugh - one poster had good reports over it - thought I'd try it since I'm organically minded) 2 tsp/gallon, powdered seaweed 2 tsp/gallon. Additions added every watering post sprout stage until the one just done - that was with the low 5 PH water.

    Now, here's the part that's confusing me. I metered the runoff and it was up in the low TWELVE range. Plants appearing to be doing fine - no worries there at this stage. Plants, btw, were re-potted into 4 gal pots right before the previous watering 5 days ago - they were light and needed to be watered.

    Naturally, this is a new meter and I'm newb to all get out on PH expectations. Meter seems to read water fine - like faucet water is in the low sevens, the outdoor water in the low fives. Meter is brand new - auto calibrated - used a couple times to see how it works and this morning to test the pot runoff.

    Not really sure how to approach this. I guess I'll do a calibration before the next watering but for the moment, the plants all had a good watering with a few minutes of runoff each with low 5 water, no nute or organic additions this time around.

    Anyone ever had healthy plants and at the same time get a ridiculously high PH reading out from runoff?
  4. First off, adding all that stuff with EVERY watering is waaaay too much. No wonder your pH is so high. Perhaps every third or fourth watering and a bit lighter on the amounts added.

    Second, get some dolomite lime, top dress with it ONCE and you won't have to worry with all this pH nonsense. Add 2tbl/gallon of container size (ex:8tbl for a 4 gal container) and it will work in with regular waterings, supply cal/mag and keep your pH in the proper range. NOT hydrated lime.

    You are complicating something simple.

  5. Thanks for the tips! I appreciate it.

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