Problems - Pics included

Discussion in 'Cannabis Pests and Problems' started by AlteaMan, Apr 4, 2007.

  1. AlteaMan

    AlteaMan Member


    This is my first post and unfortunately it's about a problem. If you look at the pics you will see that the leaves have yellowish discoloration with small brown dots and it is worrying me.

    The plants are 4 weeks old and the bottom set of leaves (and new growing ones) are ok.
    I planted in Compo Universal soil which 'should' have a fine ph.
    I water with bottled spring water
    I have fed only once with a weak solution of compo universal fertiliser (1/4 recommended strength)
    I may have overwatered but had no drooping
    I have high humidity (80%+) but I am adding a dehumidifier
    I am using CFL's at the moment

    Thanks. Hoping my first grow will work ok!!
  2. BudBill

    BudBill Dark Helmet

    Hi there,

    I took this from an old Overgrow document (I miss that site). This is a guess on my part. A foilar spray and/or mild Mg added to the waterings should help. Just don't overreact and add more nutes and water.

    Hope this helps:

    Magnesium (Mg) deficiency:
    Magnesium deficiency will exhibit a yellowing (which may turn brown) and interveinal chlorosis beginning in the older leaves. The older leaves will be the first to develop interveinal chlorosis. Starting at leaf margin or tip and progressing inward between the veins. Notice how the veins remain somewhat green though as can be seen in figure 15.
    Notice how in figure 16 and 17 the leaves curl upwards like they're praying? They're praying for Mg! The tips may also twist.
    This can be quickly resolved by watering with 1 tablespoon Epsom salts/gallon of water. Until you can correct nutrient lockout, try foliar feeding. That way the plants get all the nitrogen and Mg they need. The plants can be foliar feed at ½ teaspoon/quart of Epsom salts (first powdered and dissolved in some hot water). When mixing up soil, use 2 teaspoon dolomite lime per gallon of soil.
    If the starting water is above 200 ppm, that is pretty hard water, that will lock out mg with all of the calcium in the water. Either add a 1/4 teaspoon per gallon of epsom salts or lime (both will effectively reduce the lockout or invest into a reverse osmosis water filter.
    Mg can get locked-up by too much Ca, Cl or ammonium nitrogen. Don't overdo Mg or you'll lock up other nutrients.
  3. AlteaMan

    AlteaMan Member

    Thanks m8. Will try that and see how it goes.
  4. T.H. Cammo

    T.H. Cammo Member

    Epsom salts is like penicillin - it cures a lot of ills!
  5. BudBill

    BudBill Dark Helmet

    What makes you think its pH?
  6. AlteaMan

    AlteaMan Member

    Well I have tested the PH and it's about 6-6.5 so I guess thats ok. Added Epsom Salt to the water last night and no change yet. It seems to be getting worse with bottom leaves drying up.

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