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Orange leaf tips in LED DWC

Discussion in 'Hydroponics / Aeroponics' started by tbf, Nov 29, 2017.

  1.  
    tbf

    tbf Member

    Hi everyone,

    I have four indicas in a DWC grow tent and they have started developing orange-red spots on the fan leaves and especially the edges. All of the plants also look quite yellow as well:
     

    Attached Files:

  2.  
    tbf

    tbf Member

  3.  
    rkymtnman

    rkymtnman Well-Known Member

    EC/ppm too strong and you need some cal/mg it looks like

    is your pH ok? start with that. 5.5 to 6.1
     
  4.  
    ANC

    ANC Well-Known Member

    Dial back the nutes by a third, double check pH and calibration of your meter.
     
    Critical420 and rkymtnman like this.
  5.  
    tbf

    tbf Member

    Whoops, sorry for posting three different times, I’m on my phone and having trouble getting RIU to work right on safari. Anyways, here’s more info on my setup:

    -900W Vipar Spectra LED grow light
    -pH: 5.8
    -EC: 1.8 (varies slightly between bucket because they’re not connected, but all approximately the same)
    -I put them on a 12/12 schedule 3 days ago.
     
  6.  
    rkymtnman

    rkymtnman Well-Known Member

    1.2 max is what i shoot for. unless they need more.
     
  7.  
    tbf

    tbf Member

    Thanks for the tips. I had put in more nutes because I thought the yellow growth meant they were hungry. Unfortunately I just got out my pH meter to double check and it looks like my probe is broken: it reads 6.8 no matter what which I know is not correct. Really frustrating since that was an expensive probe. Guess I’ll have to use the indicator dye that came with my pH kit until I can get a new one.
     
  8.  
    Airwalker16

    Airwalker16 Well-Known Member

    I would HIGHLY suggest you connect them buckets together.
     
  9.  
    Critical420

    Critical420 Member

    What is average water temp?

    Do you have enough cal/mag in your water?

    Do you have your DWC air pumps on high, and are they bubbling sufficiently?

    So many things that it could be, but if you stick by these simple guidelines they should stop turning yellow:

    5.9 PH
    68-70F Water Temp
    1,200+/- PPM Nutes
    Make sure sufficient cal/mag
    Get sufficient oxygen to roots
     
    Last edited: Dec 2, 2017
  10.  
    Critical420

    Critical420 Member

    Yes, by all means use the cheap PH tester and make sure it's yellow. You can pick up a decent PH meter on eBay for $10 with free shipping. They are somewhat fragile so why pay for an expensive one? Also, pick up some PH buffer solution for $2 at any hydro store and calibrate the new meter with a screwdriver. Most PH meters will go whack if they fall in water or get splashed. It happened to mine, but it worked fine after eight hours next to the dehumidifier fan.
     
  11.  
    Airwalker16

    Airwalker16 Well-Known Member

    1200 ppm in DWC is waaay too high. I’ve never gone above 800. Most people would agree.
     
  12.  
    Critical420

    Critical420 Member

    Mine do fine at 1,200PPM with no discoloration. But the plants are massive and seem to thrive at that PPM. That's why I said +/- plus or minus. I realize some strains may not thrive at 1,200 PPM water but mine do and that's what my manufacturer's advanced nutrient schedule ends up with if I follow it. Mine are four weeks into bloom with massive nugs, probably a pound per plant when they are done. I've seen people on here post that they use 1,600 or even 1,900 PPM without nute burn, so I figured 1,200 PPM was pretty modest.

    But yeah, if my leaves were showing signs of nute burn I would back the nutes off. But if you back the PPM down too low in the middle of bloom, the leaves will waste away as the plant starts eating itself.

    Fortunately with DWC you can find that perfect balance and correct it quickly and easily if it goes out. Worse case scenario you flush the bucket and start with fresh nutes.
     
    Last edited: Dec 2, 2017
  13.  
    ANC

    ANC Well-Known Member

    What size tent is that I think I see the problem.
     
  14.  
    Critical420

    Critical420 Member

    This is not my nutrient brand (chart below), but an example confirming that around 1,200 PPM is what they recommend at this stage. But if 800 PPM works for you, that's awesome. Each to his own. We're all just trying to help each other. I just share what has been successful for me.
     

    Attached Files:

  15.  
    ANC

    ANC Well-Known Member

    1200 is fine for large "fully grown" indoor plants, the kind you would put 4 to a 1000W in 60-gallon pots.

    Only thing that looks lite in your food is calmalg, but it may be the light. Calmag nitrogen and silica make up a 80 of the earth crust... and weed likes it.

    I would swap the calmag out for Epsom salts in week 4 of flower. The plants don't need so much magnesium then and will like the sulphur in it, better.
     
  16.  
    ANC

    ANC Well-Known Member

    Most people can't even read a nutrient chart, much less do the math to work out how much actual food ends up in their pots at whatever PPM and amount used.

    Pure hydro like DWC is more forgiving in high nutes, as it stays in the mix instead of slating over media as water evaporate leaving the salts behind on your coco.
     
  17.  
    ANC

    ANC Well-Known Member

    For your size tent, you want 16 plants vegged for 10 days finishing off under 600W over 4x4,
    If you want to veg as long as you are doing, I would throw at least two more plants in there.
    A 60% full canopy can only provide 60% of the full possible harvest.
     

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