DWC grow following GH chart - Hawaiian Snow - Weird spots on leaves

Discussion in 'Sick Plants and Problems' started by northernsage, Mar 7, 2023.

  1. #1 northernsage, Mar 7, 2023
    Last edited: Mar 7, 2023
    Hey folks, first time DWC grower here so I'm struggling to find out why my plant has started to show some weird spots on its lower leaves (pictures bellow). Some more info: The strain is hawaiian snow. I have used a DWC setup with a 5 gallon bucket and two large air stones with a fairly over-dimensioned pump (so lots of bubbles and no signs of root rot so far (around 3-4 weeks into vegetation). I'm keeping water level around 1-2 inches bellow the bottom of net pot. I have been using general hydroponics flora series and their feed charts as guidelines and, so far, I had no signs of any deficiencies or stress until I noticed some weird gray-ish spots on the lower fan leaves. Temperature around 24C(75F) and air humidity in 45%-55% range, 18/6 light cycle under a 600w led board (around 60cm above canopy). PH in 5.6-6.1 range with EC around 1.7. I have searched around and couldn't find pattern quite like this (to my inexperienced eyes at least), so I'm hopping someone can offer some tips about what is causing this. Thanks in advance.

  2. what light you have
  3. Decent chance its a calcium deficiency early stage. I would bump up the calmag 1-2 ml per gallon and see if it resolves.
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  4. #4 northernsage, Mar 7, 2023
    Last edited: Mar 7, 2023
    A small full spectrum led panel, can't remember the model off the top of my head, but something like this.[​IMG]

    Edit. found some specs bellow:
    should I invest on better lights? I currently have just a single plant and don't intend to grow multiple at a time
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  5. Hm, yeah that could be the case. So far I haven't deviated from the chart and I'm using 1.9 ml per gallon. Will give it a little more and see how it goes, thanks for the tip.
  6. It could also be leaf septoria
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  7. Oh god, please, no. I went ahead and removed all affected leaves and also bumped up the calmag 1 extra ml per gallon. I might need a dehumidifier, sometimes relative humidity can go as far as 60% on rainy days and that seems to foster fungal growth
  8. that light is not 600w. but a plant will grow. those little spots can be many things, deficiencies, diseases, insects, bring the light a little closer and work with nutrients. there are things you can do now that it is not in flower, you can use foliar hydrogen peroxide to attack fungi and diseases on the leaves, and even probiotics such as lactic acid bacteria (lab) on youtube there are videos on how to make and use it, those leaves with spots will stay like that. pay attention to the new leaves that grow and those that are not damaged
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  9. Thanks for the amazing tip with hydrogen peroxide, I'll swing by a drug store today and grab a 3% bottle to make a spray solution. I also lowered the led panel to around 45cm (17.7 inches) above canopy. Fingers crossed now, hope it turns out for the best.
  10. upload_2023-3-7_10-5-25.png
    That looks like thrip damage to me. Maybe add some sticky tape to make sure.
    The higher leaves ... yea looks like caldef but could be caused by root rot.
    if anything, invest in some lighting that surrounds the plant, much more worth it imo.
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  11. I really appreciate the extra info. After a quick search I can see that it really looks like thrip issues, but my grow tent is set up in my office which is in a heavy urban area, we barely get any insects around here. After checking the whole plant with a magnifying glass I couldn't find a single thrip (or any insect at all), so I'm worried more about caldef or leaf septoria. Regardless, I got some sticky tape just to be safe.

    As I said, I have already added more calmag to my nutrient solution and also just got hydrogen peroxide to spray the leaves (also removed all affected leaves). Any other suggestions are welcome

    Hm, would you have any recommendations for which type of lights to get? Should I stick with led panels and just get a larger one? Not sure

    About root rot, I'll post a picture of my roots soon. Would appreciate if you folks could share your opinion
  12. #12 trojangrower, Mar 7, 2023
    Last edited: Mar 7, 2023
    I've not heard of anyone spraying peroxide on the leaves. It is added to the reservoir (in an attempt) to keep a sterile environment.

    A big part of the problem with hydro systems is the solution's temperature. With bubblers, I generally don't run into many problems, but I do use beneficial organisms in the mix. My other hydro system need to be cooled to ~18°C.

    Well I build a few lights, I can still get very inexpensive Influx strips (~$3) from arrow, but I still prefer to get modern lights. I have been eyeballing KingBrite's 35W panels for extra lighting, maybe add one in each corner. But I would need to contact them and ask for a daisy chained 4x 35W system which is dimmable (and uses just one driver). There's no way you want to run the lights at full blast if you are supplementing.

    I grew these autos last year:
    You can see how I added some supplemental lighting (strips) along the sides of the tent. This REALLY helped a lot to increase density and trichome amounts. Those plants were very good.

    If you do want to get some strips though, I can help you with that too, but it also means you need tools, and its the drivers that cost the most (imo).

    edit: I am trying to contact them now; will update when they reply.
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  13. #13 northernsage, Mar 7, 2023
    Last edited: Mar 8, 2023
    yeah, I had not heard about it either. But apparently it's something people do to control pests/bugs like powdery mildew for example. You just mix 1 part 3% h2o2 to 1 part water and spray on affected leaves. I did it today, will update in a few days with the result.

    Your setup looks really solid, congrats on that. And yeah, my grow space is currently a 80x80 cm (31x31 inches) with a single plant, so maybe an extra one of these 35W panels would already suffice (or maybe two?). I'll probably go for something like that once I get my issue with the spots sorted. I'm just trying not to get ahead of myself, since that's my first grow so everything is new and there's a lot of stuff to learn.
    Oh, and bellow are some root picks. Maybe someone can point out if this is root rot or not. I'm not sure since the nute solution seems to have that brown/yellow-ish coloration and there's no smell, slime or any solid formation on the water. It looks clear, but brown.
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  14. Those roots look super healthy to me.
    Well, try the calmag, hopefully that's what it is.
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