Help! Leaves Turning Brown

Discussion in 'Growing Marijuana Indoors' started by morehawes, Dec 13, 2019.

  1. Hi everyone, I would really appreciate some help on this.

    Description of the Problem

    All through veg the leaves start out well, but once they get big they go brown and crispy (photos attached). Nothing I do seems to change this. I cut off the dead leaves and try to fix the problem... and the cycle repeats.

    The plants are slowly getting larger, but I don’t want to flower until I can get to the bottom of this. So I am somewhat lost.

    The Project

    After a few successful outdoor grows I decided it would be worth growing something in the “off” season. I live in a 240sqft house with my partner and we do not have any space “indoors”. We do however have a greenhouse, so I thought it would be a fun exercise to try and figure out how to grow something in there through a Canadian winter (Pacific Northwest).

    I am finding out the answer to my “How hard could it be??? approach”... quite hard. I am at a point where I can’t get my girls happy and I’m really not sure what to do.

    • Strains: Kali Mist (left) Sour Diesel (right) – both feminised
    • Age: Week 13 of veg
    • Lighting schedule: Currently 24/0 (started out at 16/8)
    • Medium: Mix of soil from my garden/perlite/mulch (same as previous outdoor grows)
    • Nutrients: Reefertilizer grow 20-5-10, added to water as per instructions
    • Temperature: 18-22oC / 64-72oF
    • Light: LED 18 inches from plant (MARS HYDRO TS 1000W)
    • Humidity: 40-65
    • Watering: Every 5-7 days, when top 1-2 inches of medium is dry
    • Environment consistency – the outside temperature and humidity varies a lot, including below freezing temperatures. It has taken a while to get things stable inside the box, so they definitely suffered some sub-optimal temperatures and humidity early on.
    • Nutrient Balance – I started out very haphazard with my approach and simply made up a medium that worked outdoors and added the liquid nutrients as per the instructions. I did not monitor ph to begin with, but in the last few weeks have flushed the soil with mild nutrient water (PH 7). The first time I did this the runoff from Kali Mist was around 6, from Sour Diesel 7.8. I gave it two weeks and did it again, this time the runoff was mid 6’s from both.
    These girls have been through a lot and I would like to do right by them. Thanks for taking the time to read this and for any suggestions. I have heard from a few sources that that mucking up the first attempt is par for the course, which I take some solace in :)

    Attached Files:

  2. Looks like a phosphorus deficiency.

    Sent from my SM-G975U using Tapatalk
    • Agree Agree x 1
    • Informative Informative x 1
  3. Thanks for the response. Yes I had seen this and had hoped flushing with my nutrients would help, as per that article.

    I’ll try adding more Phosphorus and see if they like it.
    • Winner Winner x 1
  4. i think its a bit more then p defic .
    are you mixing the nutrients with the water then checking the ph ?
    those powder nutrients are know to low the ph down teaspoon per gallon with water that is natural 7.5 will be brought down to 3 or 4.0
  5. Yes mixing and checking ph. I wasn’t originally, but have been for the last few weeks.
  6. we will see in the next few weeks if they recover
  7. Thanks, yes fingers crossed!
  8. Since posting I have been feeding with Reefertilizer Bloom (5-30-20) to boost Phosphorus. However the issue persists. I was just away for a week over Christmas and returned to some very gnarly looking leaves (usually I cut them off before the whole leaf dies).

    This issue has persisted throughout veg - older leaves always turn brown and die. Does this still look like a Phosphorus deficiency? The pH is good.

    I am eager to change the light schedule to 12-12, but wanted to resolve this issue first. Thanks in advance for any help.

    Attached Files:


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