low run off ph - how to raise?

Discussion in 'Sick Plants and Problems' started by bobobo, Sep 26, 2010.

  1. Heya guys, got some easy ryder (autoflowering) about 2 weeks into flowering growing in soil (and perlite) under 600w hps. Fed every other watering with the canna range (2ml rhizotonic, 5ml flores, 2ml vega, 2ml boost, per litre).

    Had two plants look like the symptoms of nute burn, but the rest look nice and healthy.

    On the poorly looking two, the lower leaves have gone a pale green, and some leaves on top are crispy yellow with plenty of yellow spots and yellowing veins.

    My water is simply mains water, with a ph of 7. With all the nutes added and a bit of lemon juice the ph remains around 6.9. I added 2 litres of plain water and measured the ph of the run off, and it was 5.3 (!?!?).

    A couple of questions
    - how do i raise the ph of the soil?
    - what is draining the ph so much?

  2. yellow leaves at the top that are crispy is usually due to your plants being too close to the light, check that first

    to make ph higher you can use lime, sprinkle a bit on the top of your soil and water as usual.

    if you can get ph up and down you can make the water more alkilie (less acidic) with the ph up, i have not personally tried that for ive had no need but it would be a matter of what amounts to use to get it right.

    either way you do it you should do it gradually, and it woont fix itself insantly either you have to monitor the effects with every watering.
  3. the nute burn and the low ph are linked together. the nutes are very acid,,so they lower ph. flush out plants with lots of water.
  4. the nutes are acidic even though the ph of the water + nutes solution is 6.9? If so, how do i prevent this from happening again, or should the plants be flushed every few weeks to get rid of the residual nute acid?
  5. #5 greenhousedude, Sep 28, 2010
    Last edited by a moderator: Sep 28, 2010
    im not a pro but i dont think that its souds like nute burn personally. are the tips of the majority of leaves becomeing brown, shriveling and crispy.

    although it doesnt really matter about ph if you already have nute burn, it is what it is. if your ph is low then your getting lock out which prevents some of the nute to not be absorbed while other ones are which can cause nute burn if you keep feeding to try and correct the problem.

    but dont get me wrong you need to correct the ph and adjust the nutes, chances are you have nutes in the soil if you can raise the ph with out flushing then you should just feed with water for a while, if you do flush, then make sure ph is ok afterwards, if its not then take the steps to correct it then.

    Edit: wanted to add this to answer you whole post,

    flushing every month or two can be a good regimen to go by just to get rid of the salt build up from the nutes that you use, and yes that can fudge your ph all up as well as keeping nutes from being absorbed.

    please remember im new at this and am just using what i have read to help you use what you know already and make an informed desicion you know your plants better then we do. and pics help

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