Last 3 weeks Flowering.. lots of yellowing

Discussion in 'Growing Marijuana Indoors' started by KingsChron, Jul 15, 2019.

  1. Hey Everyone,
    It’s my first grow, I am using a hydroponic system (BCNL Roommate), and am currently growing 3x Fem strains (AK-47, Northern Lights, and Amnesia Haze). I have a 16L res that I replace weekly with RO water, sensi CalMag, and future harvest nutrients. I have a feeding schedule supplied by BCNL that I have been following. But about 4 weeks into flowering I have started to get a lot of yellowing of fan leaves. I have tried adding more N,P,K on separate occasions, it is okay for a couple days but then it continues up. I have flushed the plants with RO water and calmag-same outcome. I monitor pH daily, and it has had major spikes. I could check it today and it is 5.4, then go tomorrow and it is 6.2. I cal my pH meter every 2-3 weeks, so it is accurate. I have also found that myPPM is typically higher than the guidelines say it should be. I’m not sure how I can reduce this because I am following the regime laid out for me. I have about 2 weeks left until harvest, I’m chalking it up to a learning curve, but I don’t want to lose my girls. Any help would be kindly appreciated, I will attach pics of the plants and my feeding schedule. Thanks in advance!

    Attached Files:

  2. Most cannabis fertilizer makers recommend using too much.
    Too much fertilizer can stunt growth, reduce yield, and cause health problems.
    Over-feeding problems are unpredictable, and impossible to correct without reducing feed.

    Many of us use half strength fertilizer or less, and without boosters, teas, elixirs, etc.
    Cannabis can grow from start to finish in DWC with 300 ppm (500 scale).
    I dare not go above 500 ppm, or bad leaf health results.
    • Agree Agree x 1
  3. Well this does explain a lot. I will most definitely begin halving the intake on my last two weeks, and in my next harvest. My roots weren’t nearly long enough to reach the water res below it, overall could be a sign that they weren’t strong enough. The medium they’re in is rock wool. Would you suggest something different? Or what sort of things would promote healthier roots?
    Thank you @bkarnaze
  4. Rockwool is fine. People start seeds in it, and grow seeds in it.
    I prefer starting seeds in Rapid Rooters, then putting the RRs into netpots filled with hydroton (clay pellets).
    Next time I'll plant seeds directly into RRs in hydroton/netpots already in the hydro system, and avoid all transplanting.

    This is controversial advice (shouldn't be), but straight Clorox (2 drops per gallon per day) will keep roots healthy.
    Hydro company Current Culture sells expensive, dilute clorox under the name "UC Roots," and recommends its use along side their other nutes. Humans would hate to drink clorox, but plants like it, and it contains the nutrient chlorine.
  5. I will begin my research on rapid rooters, hopefully can find some good stuff in Canada. As far as the hydroton go, are they singular use or do you clean and reuse?
    Chlorine is okay for plants? Cause I’ve literally been avoiding tap water so I could avoid chlorine.. I am truly shocked that they would enjoy it. Do you use it from seed- bud or just in the veg state? I guess a solid flush would be good enough to clear it out after?
    Thanks again

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