Brown spots on fan leaves only

The current set up:

  1. Grow room size is 2.2"x4"
  2. Plants : Northern Lights fem and Kalashnikova - both photosynths
  3. Light: BestVa 1000w full spec LED (actual input 190w)
  4. Germination date: 28 September 2018
  5. Exhaust fan: 80m3/h
  6. Humidifier
  7. Day temp: 24.5’C (76f)
  8. Night temp: 20’C (68f)
  9. Humidity: roughly 55-60%
  10. Light schedule: 18/6
  11. Trained: LST day 22 from garmination
  12. FIMed: day 24
  13. Nutes: every watering as directions on the bottle 2.5ml/500ml water per plant!

Few burned fan leaves. But… They are like that for v long now. And its only the old ones. Does it mean anything when it’s only the bottom ones? Too much nitro? Im not too concerned about it but thought im gonna ask… Or maybe i should be?? @raustin @Familyman @ILGM.Zoe

I think it’s just looks like a little nute burn. But some of it looks further up the leaves. Let’s ask an expert. @raustin @blackthumbbetty what do ya’ll think?


There is a slight cut as well that looks like the burn goes further up but its a cut… And its only the 3 bottom leaves and Northern Lights has no duts whatsoever… Only Kalashnikova (ak & white widdow)

Have you tested the ppm’s Of the run off?? Doesn’t look to bad me.

Ppm in daily (or every second day) is around 660-700 @Familyman

You need to check the ppms in the run off to make sure they are being consumed. If they are that or higher, you will need to dial back the nutes. Also, what is the pH of your run off??

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Sorry for all the questions. Just seeing if the pH and nutes are in balance before I make my diagnosis.


@Familyman Silly me but i actually do not know what a runoff even is ;(

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The water that comes out the bottom of the pot when watering. Test it for ph and ppm

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It could be nute burn, need to know your runoff Ph and PPM.


I thought thats it but first of all i have fabric pots and second of all never had a water at the bottom. How do i check it then. Maybe i do not water enough?? Or rather than watering a bit every day i should water more every lets say 3 days? I do have a meter. And why NL is perfectly fine?

Your plants are big enough to water till runoff. If you’re not getting any runoff, then you’re not watering enough.


It takes time for issues to show. I would check them all before you have to chase them when they occur. I know my NL plants gobbled up cal and mag.

Ok i will check. Put fill 1liter of water and waiting for the runoff

I will get cal and mag on saturday

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Nothing comes out… How much water can i pump into 4gallon fabrick pot and not to overwater?

Don’t worry about overwatering. What you want to do is thoroughly water so that all the soil is wet and water comes out the bottom. Then let it dry out before you water again, that will keep it from being overwatered.

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What kind of soil are you using and what do you pH your nutrient solution to?

If I have you right, the leaves have been that way for a while and the newer growth has not shown any symptoms? You plants look pretty good. If the newer stuff is fine this maybe a problem you have past.

Before adding more nutirents, getting the runoff pH and ppm is telling. Also if those are 5 gallon pots, I would water with 3-4 liters of water. It should runoff significantly through the fabric pot.

Good luck.

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