Yellowing and dying leaves - Magnesium defiency?

Discussion in 'Growing Information' started by CallMeSteam, Jan 15, 2017.

  1. CallMeSteam

    CallMeSteam Registered

    Hi everyone. This is my first grow and my first post. I have a five week old Auto AK. Hoping someone can help me out. Lower leaves have been yellowing and a few have died and fallen off with some brown spots. Will start on a leaf as a few small spots and gets worse from there. Started low and is spreading upward. I think it's magnesium deficiency and has treated it as such. I've been using an Epsom salt foliar spray on the tops and bottoms of the leaves but the problem has persisted and is spreading. My concern now is that I've misdiagnosed the issue and that the plant will die if I don't get it taken care of. If I'm correct and it is magnesium, it's not resolving with regular Epsom salt spraying for the last week or so with irregular spraying the week before that.

    Growing under a Galaxyhydro 300w LED (actual wattage around 140) and two 23watt CFLs. Soil is mixture of Foxfarm Ocean Forest and Foxfarm Light Warrior, mixed about 60/40 but not exact. Up until a few days ago have only given PH corrected water and an Epsom salt foliar spray.

    Also small yellow tips on new growth. Started before any feeding.

    Two days ago I fed Foxfarm Big Bloom - 3 tsp per gallon and some molasses - either a 1/2 tsp or 1 tsp. Included 1/2 tsp of Epsom salt per gallon - I've avoided feeding Epsom salt to the soil but I was desperate as the yellowing has persisted. Also, two days ago gave a foliar feeding of Epsom salt, molasses and a tiny bit of Foxfarm Tiger Bloom.

    About a week ago I tested my runoff water and found the PH had gotten too low. I corrected that and since then have transplanted to a larger pot and new soil.

    I initially did the Epsom spray out of concern of a sulfur deficiency - the leaves were all light green. After only a day or two of spraying the leaves darkened a little, but then the yellowing and spotting started.

    Any help in diagnosing or suggestions to treat this and get things back on track is appreciated. Might get some dolomite lime tomorrow and top dress with a little dissolved in water. Also might get a bottle of Grow Big for the nitrogen. A member on another site said it looks like nitrogen deficiency. Would nitrogen dif cause spots like this?
    IMG_7892.JPG IMG_7898.JPG IMG_7902.JPG IMG_7897.JPG
  2. theweedsneeds

    theweedsneeds Registered+

    Well I'd say transplant it man root bound plants will do that to you Its time to give that little lady a new home her feet are to big it's time for new shoes:doublethumbs:
  3. CallMeSteam

    CallMeSteam Registered

    Thanks for the reply. I actually did just transplant her from an even smaller pot less than a week ago. It was in that tiny pot for too long. It's an auto that probably won't get that big as I'm already over 5 weeks in. That being the case, could this 2 gal pot be enough?

    I just got a bottle of Grow Big and CALiMAGic and just fed both. Thinking it's either a deficiency of magnesium, calcium, or nitrogen.
  4. theweedsneeds

    theweedsneeds Registered+

    I'm pretty sure that you were having those problems due to the plant being root bound I wouldn't try to compensate and over feed them may hurt them even more I go with molasses for my calcium /magnesium /iron all that good stuff and you only need like a teaspoon per gallon and it's organic which I'm a big fan of for nitrogen I'd suggest getting a bag of chicken Shit it works great it'll keep your plants nice and fed with a good handful tossed into the pot every so often
  5. EvilCartman

    EvilCartman Registered+

    From what's written above, I'd agree with the member on the other site. You are chasing phantoms.
    If you are growing with Fox Farm nutes, your plant will yellow-out, without the Grow Big. Guaranteed.
    The soil mix will only be good at supplying the needed nutrition for a couple weeks, at best, in an appropriately sized container. If you don't ramp-up the feeding, the plants begin to look deficient.

    There is a schedule for the FF nutes. The 3 main ingredients are made to work together. If you exclude the one supplying the lions share of Nitrogen... ;)

    (I dunno if I'd recommend foliar feeding with the Tiger Bloom, either) :p

    If you are feeding at the correct pH, don't fuss over the runoff. FF soil runoff will be low.
    (Been there, done that) :oops:
    • Like Like x 1
  6. CallMeSteam

    CallMeSteam Registered

    Thanks for the replies. I gave some Grow Big and CALiMAGic yesterday. She seems to be perking up and the yellowing and spotting has slowed. I'm optimistic. I've included a couple pictures. I'm hoping things continue to fill in. Really excited to be seeing new branches now popping through the canopy.
    EvilCartman, would FF's low runoff indicate low ph at the roots and should I be feeding a slightly higher ph to compensate or is that craziness? I'd rather not chase ph issues, which I think is what you're telling me.
    I won't foliar feed the Tiger Bloom again!
    I was using filtered water - I'm thinking that could have impacted Cal-Mag levels and worsened things.

    Thanks again for the replies. Your input is helpful. I've read posts on here for years and now that my home state has legalized it's great to be part of it.

    Attached Files:

    • Like Like x 1
  7. EvilCartman

    EvilCartman Registered+

    There shouldn't be a need. The runoff pH can be a bit unsettling, but it isn't indicative of a problem. (avert your eyes) :D
    When I used the FF line, I kept to 6.5ish. Be sure to alternate feeding/watering, to limit salt build-up.
  8. CallMeSteam

    CallMeSteam Registered

    Things have continued to rebound. The yellowing and spotting has stopped. The CALiMAGic and Grow Big seem to be doing the trick. I continued LST'ing, which I had started in a smaller pot for a little bit before transplanting and it's filling out nicely. Today I found the first pistils. Being a fast finishing auto, I expected it to start flowering a couple weeks ago - today she's six weeks old. I'm hoping the extra time allows me to make up some lost yield from the deficiencies and being in a small pot too long.

    Attached Files:

    • Like Like x 1
  9. EvilCartman

    EvilCartman Registered+

    Certainly lookin' better. First time around is a learnin' experience. :thumbsupold:
    Starting with an "auto" can be a blessing, or a curse.
    Any early issues are more problematic with an auto.
  10. gardenermendo

    gardenermendo Registered+

    The pictures of the plants after he repotted don't show it being root bound. Usually the plant would be larger than the pot to be root bound.
    I think because you gave the plant more root space and new soil, that is what rejuvenated the plant. Give it PH balanced water with Grow nutrients intended for cannabis, and upgrade pots when needed, and you wont' need all that other stuff. Don't pay attention to the runoff, as runoff will pick up nutrients from the soil.

Share This Page