1. We are currently experiencing issues with viewing and uploading images, our team is working on the issue.
    Dismiss Notice

Nitrogen Deficiency?

Discussion in 'Marijuana Plant Problems' started by iPerculate, Feb 9, 2018.

  1.  
    iPerculate

    iPerculate Member

    I've been having issues with only one of the plants in my grow tent. A few leaves, mostly in the mid-top level of plant, have some clawing and yellowing. The yellowing is starting from the tips, and also fanning up a little like they need water.

    Plants are in FFOF soil, been feeding with GH 3 part series plus some calmag and liquid seaweed here and there. I usually feed plants straight water with no nutes every other time.

    Looking through some info online it looks like it's a Nitrogen issue. I have given nutes the last 2 feedings and today is feeding day. I was going to give straight ph'd water but if there's a deficiency should I throw in some GH Micro? Is there a possibility that it's a toxicity instead?

    None of the other plants in the tent appear to be affected, all receive same feedings. Also some of the bottom branches leaves on the plant look 100% fine.

    1.jpg
    2.jpg
     
  2.  
    iPerculate

    iPerculate Member

    Here's some more pics for comparison to the other plants. She's really been slackin' lately...
     

    Attached Files:

  3.  
    Blitz35

    Blitz35 Well-Known Member

    Are these plants all the same strain? It's most definitely not lacking in nitrogen, if anything, it might have a touch too much of it. It's possible that it's magnesium related. New growth appears a slight bit thin, which can be caused by either a k or p toxicity. If you're low on magnesium, that would affect the uptake phosphorus as well. Definitely don't add extra nitrogen, as that is not what's lacking!
    Also, the leaves seem to be 'tacoing' a bit..temps may be a bit too high and/or humidity is too low.
     
    iPerculate likes this.
  4.  
    iPerculate

    iPerculate Member

    Thanks for the reply. Yeah the more I read the more it seems to be a toxicity of some sort.

    The 2 on the left are same strain, 2 on right same strain.

    I am having a thought... it is always the first plant that I water. When i water plants I mix in a 5 gal bucket and take off the top. I wonder if I'm not mixing well enough and it's getting the brute of the feedings every time. That's only if the settle to the top?

    I give them 1/2 the recommended dose of the GH nutes, and only give nutes every other feed. I do give calmag sometimes when i give them the straight water feedings, i see this also contains nitrogen.

    Humidity stays tight 58-63% day and night. Temps 73-79F

    I just soaked them with 1/4 gallon each of tap water. pH 6.7 - 75ppm. I'll probably just give them clean water this time around.
     
  5.  
    Blitz35

    Blitz35 Well-Known Member

    Maybe because it's in the back corner it gets the brunt of hotter air? Do you have a fan blowing in that direction? Have you checked the different possible phenotypes within that strain to see if maybe one pheno is more sensitive than others? The yellowing is most likely caused by a magnesium deficiency. The issue is most likely not ph related as then you'd see other problems first. Though ph of 6.7 is a bit too high, you should keep it to lower 6's, ideally under 6.4. Try some epsom salt instead of cal-mag. How old is the medium you are using? Any possibility of a sodium build up?
     
    iPerculate likes this.
  6.  
    iPerculate

    iPerculate Member

    Yeah I have a 6 inch oscillating fan as well as 4inch exhaust with the charcoal filter. Also there are intake vents on the bottom by this plant. I have given plenty of Calmag during the grow, it's hard to imagine its a mag deficiency, but that's why i'm here. I transplanted into these 7 gallon pots just under 1 month ago, so the medium is pretty fresh.I don't have any epsom salts but I can get them if I need to.

    Should I go for a flush?
     
  7.  
    Blitz35

    Blitz35 Well-Known Member

    I don't have experience with ffof, cant get it here, but ive heard over and over that it's a 'hot' mix. i use gh flora as well, only the micro and bloom, i use gh silica instead of the gro. What amounts are you giving of each in how many litres of water? Plants are funny at times..i have two auto critical kush's going in exact same mixture side by side with exact same feed, and in 2 waterings, once flowering, i see i will have to give them different feeds. How much of the bloom gh are you adding per gallon of water? Asking because that's the one that contains the mg and sulfur. Adding cal mag (which usually contains nitrogen) and too much micro, with a hot soil, can create a slight nitrogen toxicity. The extra potassium from the 2-1-6 gro and again the calcium in micro and maybe from your tap water if that's what you use (plus the hot soil), can lock magnesium out. It can all originate from too much nitrogen (you have some clawing)..that would leave an excess amount of potassium in your medium and that in turn would lock magnesium out. Does that medium dry out at the same rate as the one next to it of the same strain? Im not sure if a flush is necessary..what week are you in, when are you flowering?
     
  8.  
    iPerculate

    iPerculate Member

    The last 2 feedings - Per Gallon;
    2ml Micro
    2.5ml Gro
    1ml Bloom
    1ml Calmag

    3 gallons total for the 4 plants.

    When I water without feeding, sometimes ill still give them calmag and/or liquid seaweed, but only at 1ml/gal.

    I do use tap water, comes out around 75-100ppm. The medium does dry out around the same as the other plants. I am going into week 6 of veg, I plan on switching to flower in 6-9 days, but can push that back a little if needed.

    I just finished giving them their full water feeding. Maybe I'll keep Micro out for the remainder of the grow, and cut back on it next time.
     
  9.  
    Blitz35

    Blitz35 Well-Known Member

    Don't keep it out for the remainder of the grow! She will and may still need the micros now, just up the magnesium. You can get some epsom salt at the dollar store. once you start flowering, she will be even more hungry for magnesium and the problem can show more. Keep it the same, just a slight cut back to overall nitrogen going in and raise the mg. just don't overdo it as that can cause issues elsewhere. keep mg and p to a 1:1 ratio.
     
    iPerculate likes this.

Share This Page