Possible magnesium deficiency?

Discussion in 'First Time Marijuana Growers' started by fleshcage, Mar 10, 2016.

  1. #1 fleshcage, Mar 10, 2016
    Last edited: Mar 10, 2016
    Hi. I'm a first time grower and i'm experiencing some problems i'm not sure how to adress.
    Most of the leaves looks fine and dandy but since last week i've started to see some stains on some of the old and newer leaves alike.
    From what i can gather on forums and literature over the net it looks like an early stage of magnesium deficiency to me, but im not sure.
    It's not spreading rapidly nor is equally distributed among the foliage.
    my setup is a drip hydro sistem on perlite, 11 liters pot. i switched on a 400w HPS bulb last week (before was a 400w MH) along with a flush and with flowering nutes. ph is 6.2. the roots have outgrown the pots (probably because the dripper cover just a small portion of the pot?) and they're dipping into the reservoir, so i added an areator to keep the solution well oxygenated, they looks healthly white and they're not giving any strange smell.
    strain should be an auto lemon skunk, other than this i don't know really much since the seller was kinda shady.
    thank for your time.

    http://i.imgur.com/8Bi6KTf.jpg

    http://i.imgur.com/jaNald0.jpg

    http://i.imgur.com/R4Hf9ia.jpg
     
  2. i see the spots in the first two pics. looks like magnesium deficiency, good d/x!!
    pick up some calmag to treat the deficiency

    healthy looking plants otherwise. i see preflowers :)
     
    • Like Like x 1
  3. thank you for the answer!
    yes, they started to flower a week ago :)
    still, i'm not sure what's happening here because i'm using tap water and i have a pretty hard one, around 0.45 EC, so i thought the last of my problem would have been a calcium/magnesium deficiency...
     
  4. If your water is softened... then the EC will be high, but the multi-Valent metallic actions are removed (notable ca mg or any other +2 metal)
    ... the sodium or potassium that replaces it continues to show high TDS, even though there is no mineral value left to your plants.

    210 watt perpetual box
    https://forum.grasscity.com/index.p...att-3.5-sq-ft-Northern-Lights-and-White-Widow:
     
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  5. thanks for the explanation, that was a really useful info.
    I was totally excluding thechance since i always have very heavy residue left by my tap water on the surfaces and i thought it was from calcium...
     
  6. Calcium won't leave residue unless you heat ( boil ) it. Magnesium won't leave a residue unless you evaporate nearly all of it.

    If you get white water spots... it is likely plain old sodium.

    ...are you on a well ? Public supply? Is it legal to say whereabouts you live ?

    210 watt perpetual box
    https://forum.grasscity.com/index.p...att-3.5-sq-ft-Northern-Lights-and-White-Widow:
     
  7. unfortunately not :p water comes from the local area aquifier, so i guess all this is starting to make sense...
     

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