Yellowing of leaves.

Discussion in 'Coco Coir' started by addski, Jun 2, 2012.

  1. Hi guys i have Lemon kush cuttings in my wardrobe there 3/4 weeks into flower , i have only been getting this with the new blackstar i have a fair bit of experiance with growing in coco and with hps and never had any problems like this.
    Im getting yellowing/browing off my fan leaves and i cant for the life of me work out what it is or fix it!!! (had same problem with crazy miss hyde , under the 240).

    lets start with setup and feedings.....

    240w uv blackstar
    growing in Coco
    temps constant 24.2 lights on and 21 lights out.
    canna coco a+b
    sensi cal/mag
    buddahs tree 9/18
    rhizotonic

    There on 1.8ec and 5.8ph and run off ph is 6.7 last feed.
     

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  2. [quote name='"addski"']Hi guys i have Lemon kush cuttings in my wardrobe there 3/4 weeks into flower , i have only been getting this with the new blackstar i have a fair bit of experiance with growing in coco and with hps and never had any problems like this.
    Im getting yellowing/browing off my fan leaves and i cant for the life of me work out what it is or fix it!!! (had same problem with crazy miss hyde , under the 240).

    lets start with setup and feedings.....

    240w uv blackstar
    growing in Coco
    temps constant 24.2 lights on and 21 lights out.
    canna coco a+b
    sensi cal/mag
    buddahs tree 9/18
    rhizotonic

    There on 1.8ec and 5.8ph and run off ph is 6.7 last feed.[/quote]

    If you're going to measure the runoff pH you may as well measure the runoff EC. The pH buffer of coco will never give an accurate pH on the runoff but the runoff EC can be used to determine of there is buildup in the coco. In your case, I believe buildup to be the likely culprit.

    Looking at the leaves I am leaning towards a cation imbalance. Probably too much calcium retained in the coco preventing the uptake of potassium and magnesium, and probably messing with the phosphorus as well. My suggestion to you is to cut the Sensi cal/mag way back. Maybe to none at all for a while. Canna AB has plenty of calcium to begin with anyway, although you are going to need to "fight" this deficiency a little.

    I suggest a feeding of 5ml a+b per gallon, 10ml rhizotonic, and 2ml of the Buddhas tree, with an extra 1.25g of Epsom salt for the mag boost. This should be about a 1.2 or 1.4 EC when mixed and offer a balanced npk ratio with less calcium. Get a good deal of runoff with this lower strength solution and that will help remove buildup without destroying the balance of elements retained by the media.

    Simply though, you have been over feeding. Cut back your EC and you'll see improvement but I think that dropping the sensi cal/mag is going to give you the best results in the long run.
     

  3. Ok brilliant thanks very much , and it makes sense as the sensi cal/mag is new to this grow since i got the LED.
    Normally i would just run canna a+B , rhizotonic , pk 13/14.

    Again thanks for the great explanation its explained it brill. :hello:
     
  4. OP I have the same light and having pretty much the same prob with my coco grow. Flushed to 0.2 EC run off and cut down on the cal/max yesterday so I hope to see some improvement myself. Running canna a+b and all canna supps at heavy feeding from the canna website. My rain water is only 30ppm and tap water here is about the same.

    Hope you see some improvement soon.
     
  5. lol.

    "Only Kelp and water" really means kelp and water fed to a soil mixture that contains all sorts of sources for nutrition.

    The guy is in coco. Maybe we should help him resolve the problem before redesigning his entire setup to something he obviously didn't want in the first place. Maybe...
     
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