Yellowing lower leaves

Discussion in 'Marijuana Plant Problems' started by 1212ham, Jan 10, 2018.


    1212ham Well-Known Member

    It's my first grow. 6 weeks from seed, still in veg. Fox Farm HF soil in 1 g plastic pots. Watering every other day. Started feeding 2 weeks ago with Mega Crop, every watering at 2 gram/gallon. They are often drooping, seems to be random. Humidity has been 15-30%, temp 66-75F (19-24C) Saw first signs of yellowing a few days ago, much worse today. Can't get pics until tomorrow. Opinions? I posted in the newbie section and are people asking about humidity and telling me to re-pot etc. etc. but no explanations.
    Last edited: Jan 10, 2018

    jemstone Well-Known Member

    Humidity too low. If you live in a desert environment you will need a humidifier. Back off watering and food. Let soil dry out a bit. Apply a good compost tea.

    Ablaze Well-Known Member

    Without pictures it's very hard to say. We each see our ladies differently, and what you're describing are just symptoms.

    You're growing in soil, and good soil at that. Being a first grow, there is a very good chance you're over watering. The container should feel very light before you need to water again. Almost like you'll be surprised at how light it will be when you pick it up. If you put your finger way down in the dirt and can feel anymoisture, then there is probably a good chance you don't have to water yet. My suggestion is to back off on the watering. If it perks up then you know you're killing it by loving it too much.

    Adding nutrients is like walking a tightrope. One slip up and you're toast. Just like the tightrope walker, take your time.

    1212ham Well-Known Member

    Let me know if these pictures are good enough. I've been watering with about 8-10 ounces every other day for weeks but the yellowing is new. Pots are light and a moisture meter shows dry to the bottom of the pot after 2 days. Just got a lux meter, 27000 at the top of the plant.

    Attached Files:


    dtl420 Well-Known Member

    That looks like nitrogen deficiency. I have no doubt that a plant that size in a pot that small in a grow room that dry will need watered frequently.

    I would give them heavier feeding, but less frequent. Like once a week and water as needed. Definitely try to get the humidity up, but it won't kill them where it's at. Probably would solve a lot of issues if you got bigger pots and potted up. 1 gallon of soil can only sustain a plants nutritional needs for a short veg, and it definitely can't hold onto enough water for conditions that dry. 7 or even 10 gal fabric pots may be more up you're alley. I use 15, I've also got a few 17 gal pots laying around here somewhere, they hold more water and nutrients for the plants.

    My grow room is just as dry though, and I don't have these issues, so I wouldn't blame it on humidity. That is a Nitrogen deficiency.

    What's your exhaust system like? And are they in a tent? Excellent pictures btw, I wish everyone asking for help would post pictures that clear.
    1212ham and Ablaze like this.
    Buba Blend

    Buba Blend Well-Known Member

    Just my 2c.
    I would transplant to the pot you plan on flowering in and only give them water for a while. The new soil will feed the plant.
    If you don't get a humidifier you can put a couple of damp towels in the room to bring up the humidity some.
    1212ham likes this.

    1212ham Well-Known Member

    Thanks for the insight. I now think the soil was seriously depleted by the time I started feeding. That, and I overlooked that I had increased the light level when I installed my new light build over a week ago, see post #1806,

    I plan to transplant to Fox Farm Ocean Forest tonight in 3 gallon fabric pots. I also put a small warm mist humidifier in the tent.

    Ventilation is probably poor, just open vents on my 20" x 36" x 53" tent. It's going to be tough keeping temperature and humidity up with forced ventilation. Any rule of thumb for airflow needed? Thanks for the comment on my pictures, I didn't even have the camera set for close-ups!

    1212ham Well-Known Member

    I'd love to hear your thoughts on this. What I read concerns heat removal and odor control, but what about plant health?

    They looked rough last night. I should have taken pics. Assuming a deficiency, I transplanted to Ocean Forest in 3 gal. Smart Pots. They look better today.

    dtl420 Well-Known Member

    I was going to tell you to tone down the exhaust if you had it. It also concerns humidity a good deal. As water evaporates and the plants transpire, the RH will go up. A properly exhausted grow room will stay dry. Considering you're growing in a tent and your RH is that low, you don't need exhaust right now. Unless you're growing in an airtight room your plants can breath well enough, especially considering there's only a couple of plants.

    They'll always look pretty rough after transplant. They go into shock, typically quit growing for a few days, then bounce back better than ever. Being in fresh FFOF, you shouldn't need to worry about deficiencies for at least a few weeks. Just give them straight water, maybe an occasional compost tea.
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