Potassium or something else?

Back in the game and having issues with my first round back. Any suggestions would be much appreciated!





Plants were soil clones transplanted to my rdwc system on 8/13.
Temp. 77-80 lights on 70-75 lights off
Res temp- 66-67
Using general hydro nutes Lucas formula 530-540ppm is where they hover, doesn’t seem to move. Calibrated meter twice over last week and reads great
Ph 5.8-6

Please let me know if I’m missing anything that will help diagnose.

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I get leaves like that sometimes due to lighting. I have to back off on the lights a bit.
Adding silica can help make the plant less sensitive to light burn.
If its a potassium def then the leaves will come off easily with a very gentle pull. If the leaves are still firmly attached then its light burn. In this type of case the light burn can occur on random leaves and not always on top. Check air stone or air flow to roots too.

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After looking at a ton of photos of light burn and my leaves being tough to pull off, I think you’re right! Lowered the LEDs a bit and raised as well. Will see how the react. Last grow was with HID so leds are a first, honestly should’ve thought of that earlier.

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Its actually not the first thing we think of when seeing leaves like that.
And “Light Burn” more often is caused by very close proximity to lights and in a far more obvious way.
It took me a year to figure it out as I was growing clones that were doing it the same as the mother plant did. Found the answer finally on another website that sells seeds.
Some of the informational articles on Royal Queen Seeds is very good.

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Hello @Mittenman99. Plants do look a little spent. You’ve provided some information about your grow. If you can give us more info it will help us provide a more thorough analysis of your situation. Where’s the Nitrogen??

Answer these simple questions the best you can. If you are not sure, just bring it to our attention. We will figure it out.

  1. Indoor or outdoor? - size of grow?
  2. Otigin of seeds?
  3. Regular, feminized, or autoflower?
  4. Origin of water. PH, EC/TDS of source water?
  5. PH and TDS/EC of if mixed solution?
  6. Grow method? Soil, Soil-less, Coco, Hydro, Aquaponics. Please explain.
  7. Nutrients or fertilizer system used.
  8. What typr of lighting are you using? LED, HID (MH, CMH, HPS), or Fluorescents? Please elaborate.
  9. What are the temps in your growspce? Day / Night?
  10. What is the RH = relative humidity in your growspace? Day / Night?
  11. AC, Humidifier, De-humidifier?
  12. Do you have a Ventilation system? Size? 4", 6"?
  13. Co2 Yes / No?
  14. How long have you been growing?
  15. What budget have you set in order to grow successfully?
  16. If you grow hydro, then please explain your hydro method. DWC, R-DWC, Ebb and Flow, Or; Other? Other?

16b. Size and temperature of solution in reservoir?

From my limited knowledge of GH Lucas formula, 7 minutes google school, your not providing the proper nutrients. Lacking the Nitrogen needed during vegetative growth. I also use Beneficial Microbes to keep my root zone happy and healthy.
With RDWC you should have seen some explosive growth by now.
I too use GH Flora series but I’ve been using the following feed chart.

With a DWC grow your lacking lots of “stuff” soil provides. Not just the base nutrients but also things like magnesium, calcium, silica and iron to name just a few.
Also living in water in a warm/hot environment bad microbes can invade and cause damage to your roots. Using a product like Botanicare Hydroguard is a must in your type grow.

What does your roots look like?

Appreciate the reply! Answers to best of my ability as passenger on way to birthday party lol

  1. Indoor or outdoor? - size of grow?
    Indoor, roughly 12x12 room

  2. Otigin of seeds? Local clone company, reputable on local grow group

  3. Regular, feminized, or autoflower? Clones

  4. Origin of water. PH, EC/TDS of source water? Tap, 7.0ph and 140-160tds before adjusting

  5. PH and TDS/EC of if mixed solution? 580 5.9ph

  6. Grow method? Soil, Soil-less, Coco, Hydro,
    Aquaponics. Please explain. Homemade rdwc basically same concept as a current culture system

  7. Nutrients or fertilizer system used.
    Lucas formula

  8. What typr of lighting are you using? LED, HID (MH, CMH, HPS), or Fluorescents? Please elaborate.
    6 hlg 550s

  9. What are the temps in your growspce? Day / Night? 75-79 day, 72-74 night

  10. What is the RH = relative humidity in your growspace? Day / Night? Roughly 55%

  11. AC, Humidifier, De-humidifier?
    AC/ humidifier, haven’t had to lower yet

  12. Do you have a Ventilation system? Size? 4", 6"?
    8” infinity

  13. Co2 Yes / No?
    No

  14. How long have you been growing?
    Years ago Before I moved grew 6 crops with HIDs, only difference is now I have LEDs

  15. What budget have you set in order to grow successfully?
    Can add whatever I need at this point honestly.

  16. If you grow hydro, then please explain your hydro method. DWC, R-DWC, Ebb and Flow, Or; Other? Other? RDWC, have a water chiller for setup running as well.

16b. Size and temperature of solution in reservoir?
65-67* with chiller, I believe it’s a 50 gal black tote ( verify when home)prolly 25-30 gals in it.can provide root pics when I get home tonight.

Thanks again

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First off I would be adding silica (as pointed out above) and cal mag as I see some interveinal chlorosis. I would also suspect a root issue: can you get a photo of roots?

Overall light color indicates you could up the TDS of your nutrient load: I’d shoot for around 900 ppm.

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