Rust spots, Yellow tips & rising pH

Discussion in 'Sick Plants and Problems' started by southern_lights, Feb 20, 2009.

  1. New to growing hydroponically, so i got some nice pics and hopefully someone can point me in the right direction...

    Medium is perlite
    Light is 400wHPS
    Water is 15mins once per 2.5hours
    have lots of airflow
    resivoir is not dark (fixing that today)
    air stones recently added

    My main concern is the pH rise im currently flushing and the start pH of 6 is rising to 6.4 with 15mins constant water. And im at the 3rd flush... is this likely to indicate some sort of disease? what can be causing such a pH rise. I also suspect Mg deficency due to the pale new growth and leaves cupping up ( i got epsom salts to fix )
    Ty in advance.

    Attached Files:

  2. What kind of hydro setup, ebbnflo, DWC?

    What is your ppm, feeding schedule, and nute types?

    Are you using tap water or RO?

    Your ph should be around 5.8 unless you are using aeroponics, which is 5.6.

    You are better off using cal mag instead of epsom salt for a deficency.
  3. #3 southern_lights, Feb 20, 2009
    Last edited by a moderator: Feb 20, 2009
    Im growing in Perlite, Using drippers to feed. I use tap water which i leave out overnight before adding to the rez. I previously didnt have the pH swing using tap water leading me to believe theres some nasties growing on my babes causes rapid pH rise.

    Im running 1000ppm

    I normally run at 5.8 and let it drift up to about 6.1 (usually takes a few days) but was starting with pH of 6 due to the large swing (didnt want my babes jumping from 5.8-6.4 within a few hours)

    They are watered every 2.5hours 3 is recommended for perlite but it seems to get a lil too dry by that stage.

    I'll try and get some calmag from the hydro store after the weekend, till then i'll prob just use epsom salts since i got some.

    Its prob worth adding the yellow/brown tips and rust spots are getting worse and starting to effect the newer growth.
  4. To be honest, that just looks like good-ole nutrient burn to me. From the sound of things, you've got your sh*t together, so I'm not worried about you, man. Your PH spike is probably from a buildup of salts since you're already in flowering and have been feeding quite a bit through veg. I wouldn't get too concerned about a mag deficiency....tap water has enough in it already.....your shower door gets a buildup of this every few weeks, right? So, I believe we can rule that out. Just keep flushing with PH-corrected water and you'll see things get better in a few days. Return to half-strength nutes for a few weeks and by then you'll probably be ready for final flush before harvest.

    Good Luck!!!
  5. Just want to share the reasons for the problems i been having.

    I've had a buildup of salts due to neglecting to top up the ammount of water used each day. Meaning each day my nutes we're becoming more concentrated leading to mild nute burn.

    The pH swing is actually due to the airstones i recently added, they've been running 24/7 forcing the Co2 from the water and causing a rise in pH. I read about 15-30mins of air b4 each water is fine. Its worth mentioning ive got small resivoir (25L) (6 and half Gallons) so it needs very little air really.

    The yellow tips i have suffered from week 1 of flowering, likely calcium deficency due to incorrect pH. Please correct me if im wrong there.

    Today i'll finish flushing and tomorrow resume half strength nutes.

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