Is this potassium deficiency?

Hey all,

Newbie grower here. I'm growing a couple autoflowers in soil under LED.

Soil: 3 parts generic potting soil mix, 3 part perlite, 2 part store bought compost, 1 part worm casting.
Light: 5x Gen7 Vero 29 @50W each (3500k). Lights are kept around 18in away. 20/4 schedule.
Temp: Sits around 75 degrees, but I did see it dip down to around 60 during the night. I've been keeping the windows closed to prevent the temp dip during the night.


She is about 4.5 weeks old and started flowering about a week ago. Seems relatively healthy, but I'm not sure if what I'm looking at potassium deficiency. A few of the bottom leaves have started turning yellow as well, so I'm guessing nitrogen deficiency is in there as well. I haven't fed any additional nutrients so far. I was hoping that the soil would be enough. If it is deficiency, I'm guessing I would need to start feeding some bloom nutrients at this point? I have dyna go grow and bloom.

Any help or additional advice to help out my girls would be much appreciated!

back off the dynagro.

polishpollack said:

back off the dynagro.

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I haven't fed any nutrients for the entirety of the grow thus far. Only plain phed tap water.
They have been grown with just the soil mix mentioned above.
Are you suggesting that this is a burn rather than a deficiency?

rotten chestnut said:

I haven't fed any nutrients for the entirety of the grow thus far. Only plain phed tap water.
They have been grown with just the soil mix mentioned above.
Are you suggesting that this is a burn rather than a deficiency?

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Yes It looks like a nutrient burn to me as well.

Its the next day amd the problem seems to be getting worse. If it is a burn, do I need to give it a flush?

If you've had these in that same soil since a seedling and it's survived to this point it shouldn't be nute burn.
I would water with a LITTLE cal mag and raise your lights to 24" to 26" and see if it helps.

Capn-Crunch said:

If you've had these in that same soil since a seedling and it's survived to this point it shouldn't be nute burn.
I would water with a LITTLE cal mag and raise your lights to 24" to 26" and see if it helps.

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Awesome. Thank you.
The plants have been in the same soil since seedling. I will try and do that and see if it helps.
Just for future reference, is it a deficiency I'm looking at?

It looks like it to me. I had the same looking leaves on autos that I grew
Don't keep your lights close as well