Help identify deficiency (guessing Mg or Ca)

Discussion in 'Sick Plants and Problems' started by trihelix, Nov 29, 2011.

  1. #1 trihelix, Nov 29, 2011
    Last edited by a moderator: Nov 29, 2011
    I've got a Super lemon haze (from seed) about 4 weeks into DWC that has got some issues by the looks of it.

    1. Leaf edges curling up towards light
    2. Old tips drying, dieing and losing colour.
    3. Old leaves have green veins but are yellowing in between leaves.
    4. new leaves start off fine but after a week start to experience same symptoms.
    5. So far issue is only happening on fan leaves, only noticed a single leaf on a shoot turning brown.
    6. Possible slow growth, the plant seems very small for ~4 weeks.

    Some important information:

    With the exception of the first few days, PH has hardly moved in either direction (~5.8-6)

    with the exception of when I add new water (~200ppm tap PH'd down), the PPM level appears to be slowly rising.

    My take

    The PH drifts to 4 and 7 in the first week could potentially be locking out Ca and Mg, I foliar fed Mg last night and will report back tonight on the success. This deficiency would account for the leaf tips curling up, leaf tips dying and stunted growth.

    Burnt tips could also be caused by nutrient burn, although the plant is lacking most of the signs from what I could find to identify the problem as nutrient burn. Also, the PPM levels not falling would indicate the plant is being over fed. As a precaution, I watered down my reservoir last night and am currently sitting at ~300ppm.


    Picture of damage 1

    Picture of damage 2

    PH Chart from day 1

    PPM Chart from day 1

    Temperatures from day 1

    Information requested by the professionals:
    What type of medium: DWC in hydroton
    Indoors or outdoors: Indoors
    What strain: SLH
    How old are the plants: ~4 weeks
    What type of lights and how many watts: 400W MH
    How far from the lights: ~3" + air cooled hood.
    What is your watering frequency and source of water: PH'd tap water @ ~200ppm
    What, how much and when was it fed? fed around week 1 via 0-5-10 lucas method at half strength.
    What is the medium/runoff pH and PPM if in hydro: info listed above
    What are the temps and humidity in the room: info listed above
    What size pots: 5G
    Any bugs? Look real close: No
    Any other pertinent info: No
  2. looks like MG deficiency to me try adding some epsom salt

    how much is hard to guess... you can do the calculations but it's up to the plant as to how much it needs. I've seen people say from 1/8 tsp to 1tbls /gal

    I'd say add a small amount to your bucket and see if things darken up a bit in a day you can always add more but to remove it you need to change the water or add water and nutes...
  3. i have soil but i use it at 1tsp per gal.

    and round of applause to trihelix :hello: , you are ahead of the 90% (roughly :smoke: ) of the other growers on here by making charts like that.
  4. Thanks guys. I did a foliar spray with 1/2 tsp in 0.5g so we'll see how it looks in a few days!

    Good to hear :smoke:, I made them in google docs where I keep track of my readings.

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