Orange and brown rusty spots on fan leaves

Discussion in 'Growing Marijuana Indoors' started by joegeezer, Apr 15, 2017.

  1. Can anyone tell me what this is I have checked deficiency charts and still can't tell 100% what it is. makes the leaves brittle in places and the tips go dry too. also small tears appear.
     

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  2. Could quite possibly be the start of something known as "Rust Fungus" . However, I wouldn't be of any help because I don't have a clue on how to stop such a problem.
     
  3. That looks like nutrient feed water splash damage. You don't want to leave splashed feed water full of nutrients on the leaves. It will burn holes like that. If you don't think that's what it is it could be calcium deficiency but it doesn't really look like it to me. I'm leaning toward splash damage. It appears to be just more on the one leaf.

    Phosphorus deficiency is common and also causes similar browning to calcium def. Cannabis is a phosphorus hog. It's typically the highest % number in any feed schedule for cannabis. I use up to 45% phosphorus GH dry koolbloom when I'm finishing a ripe plant. I've got phosphorus deficiency from using grow nutrients that are too low in it for too long. Most bloom schedules have a huge boost in phosphorus. If you have a bloom component to your feed try boosting that a little.
     
    • Agree Agree x 1
  4. When watering I have never got water on leaves. I'd say 25 % of the fan leaves have this and one of my plants from my last grow had this too. this plants still in veg you can see where Its killing leaves.

    I am using westlands multipurpose spoil with added john innes with 80:20 perlite. transplanted to 10litre bucket two weeks ago but was already getting this problem before transplant. watering twice a week with no nutrients.
     

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  5. Can you take a better picture there. More the better.

    I was honestly thinking it looked like some nute water got on the leaves as well.
     
  6. With calcium deficiency the rust spotting is smaller. Less large blotches.
     
  7. More pictures
     

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  8. More pictures. so do you think it's definitely a phosphorus defiency?
     

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  9. Yeah, It's not that severe but I've had it before. The plant took off once I corrected it. I started some plants with GH floranova grow trying to do a one part nutrient experiment. FN grow is 7-4-10. There's almost twice as much nitro as phosphorus. Horrible balance for cannabis. I got phosphorus deficiency and switched to vegging with FN bloom. It's 4-8-7. Double the phosphorus compared to nitro. The plants loved it. Some research later revealed that FN bloom is very close in feed ratios to the lucas formula and some people use it instead of buying the standard flora micro and bloom.
     
  10. When in doubt, flush it out
     
  11. The problem is if it's a deficiency flushing will make it worse. If the deficiency is caused by a ph issue then flushing may help. I think this is a true phosphorus deficiency myself. It needs richer p&k feed not to be more watered down.
     
  12. Flush would be a great starting point


    You could be watering more too
     
  13. hey bro it almost looks like rust (airborne disease caused by shitty ventalation). are you replacing old stale air with fresh? you said you had it also on a previous crop? curious to your ventilation... it will usually attack weak plants and generally will appear more in flower when plants are trying to reproduce and not in survival mode but it very well could be. pics are so hard to diagnose
     
  14. To me that looks like root rot. I had the same problem before. I don't think it's a deficiency.


    Sent from my iPhone using Tapatalk
     
  15. If it was hydro I may agree but this is soil of some type. Root rot is very unlikely. It's mostly the light too close but those brown blotches are lack of phosphorus. The plant wants to take off but it can't get enough feed because of either ph or the soil isn't rich enough. Hard to have a perfect guess from a few pictures but that's what the plants are telling me.

    A major part of learning to be a good grower is learning what the plants are asking for. They don't use words they use their leaf condition and posture to tell you what they want. You just have to learn their language. It takes careful attention to a few crops start finish and a little time.
     
  16. I've been and bought some bone meal this morning. looked at all my nutes and soil npk ratings that I have been using for the last few months and they are all lowish in phosphorus. As for root rot I never over water and always allow the soil to become almost dry before I water again. ventilation is ok only 1 plant in tent at the moment with a fan drawing air in from the bottom and all other vent holes open. planning on this plant being a mother plant so I wont be flipping it anytime soon. had to plants in this tent last grow the smaller of the 2 never experienced this but the larger did, I'd say that would show it's not fungus if both never got it and the larger plant needing more nutes would show a defiency before the smaller plant.
     
  17. Flush and correct the ph and get the ventilation right in the grow room, the rust fungus will rub off on your fingers it's not that, try it, but the rust fungus is easy, just cut the bad spots out of the leaves. Burnt tips are too much nutes. The soil had the nutes the plant will only take so much lol, its too much it don't like, don't believe the sales pitch of giant buds they just want to sell you what you already have lol. Ph is generally high I use lemon juice to drop ph. The walls to the tent should be sucked in with proper ventilation.
     
  18. I am sure the plant has been smoked by now......
     

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