Mysterious deficiency

Discussion in 'First Time Marijuana Growers' started by jayrollin, Jun 14, 2019.

  1. Hi guys, first time grower here. I have this mystery deficiency that is progressing through my plant.

    Bagseed, using FFOF with about 20% perlite mixed in a smart pot (fabric). Humidity around 45-65%, temps 72F to 78F. PHed to 6.2-6.5. I originally was using store bought distilled water but switched over to brita filtered water from the tap after finding out distilled water may be the cause due to missing minerals.

    The problem presented mid to late veg and has only accelerated since then (now on Week 3 of flower). It appears to be a mobile nutrient due to it moving up the plant. I've been feeding only lightly in late veg and medium to heavy feeding in flower. I've been using liquid seaweed, cal-mag and FoxFarm tiger bloom. I've tried upping the cal-mag dosage to 10ml per gallon and it appears to have had no affect. Switching to tap filtered water seemed to have no affect. Stems leading the the leaves have turned reddish/purple, and it does not appear to be a genetic thing because soon after the stem turning the leaf becomes affected.

    I'm not sure where to go from here, soon my sugar leaves will be next, any help would be greatly appreciated, thanks!
    And if this is in the wrong section sorry, please move to where it needs to be, thanks.
    [​IMG] [​IMG] [​IMG]
  2. Hi Jay. Welcome to GC.

    Since you're in flower now, it's probably a potassium deficiency. Watch this video and see if what is explains matches up with what you saw the plant doing.

  3. Hi Sticky! Thanks for the welcome and video. I suspected it may have been potassium, I have pretty much every symptom he described minus the heavy green foliage before the browning. My (newer) leaves have almost a bluish hue to them.

    I'll try dropping the cal-mag dose to 5 ml and upping my PH to 6.5-6.7. But should that alone work? It seems like such a minor adjustment. I checked my foxfarm tiger bloom bottle and it lists " derived from:...potassium phosphate " so surely it must contain some potassium right?
  4. You're right about distilled water. You need to give Cal-Mag otherwise they won't be there. However, the Ca and Mg deficiencies aren't the cause of the potassium deficiency you're seeing now.

    I've been using FF liquid trio and water soluble trio now for about a year. You need to start providing the the Tiger Bloom about 3 to 4 weeks at least before the flip. That will eliminate the problem you're seeing now.

    Don't drop the Cal Mag dose. Since you're in soil it's a bit easier to manage than in hydro. With mine, I rotate high and low ppm of nutes every other water. Potassium AND Nitrogen can each cause a lock out of Ca and Mg. I use the Cal-Mag and Big Bloom in the low ppm feed and put the Tiger Bloom and Grow Big in the high ppm, though you don't need to give N more than like a half tsp per gallon maybe twice through all of flower.

    If you aren't using the water soluble trio, I highly recommend it. ;) Keep them in the high ppm feed as well.

    There are interactions of nutes you need to be careful of, Jay. Read this one. It might take a few times through to really understand it but, you'll get it.

    Playing By The Rules : Biochemical Sequence, Nutrient Antagonism
  5. Gday bud, im gonna have to say it's a "P" Deficiency. Your bluish green is the tell tail sign.
  6. Thanks for the replies guys. Based on what's been said, would my best course of action be to continue feeding my normal dosages?
    If it is a P deficiency would upping my Tiger bloom dosage help? I've been considering some form of lockout but I can't imagine what kind of lockout it could be, seeing as my PH is where it needs to be. Could the high dosage of cal-mag lockout the P?

    I think I might bring the cal-mag back to a normal dosage and up my tiger bloom to heavy feeding. Thoughts?
  7. You would be better off to use a P & K Booster as your flowering plant want's these 2 elements a lot more now.

    Ps, you need to be sure it's a deficiency and not a lockout caused by the use of to much fertiliser before up any dosages.

Share This Page