Potassium Soap burning plants


Well-Known Member
Hey guys, I've been dealing with thrips and using potassium soap and neem to control them.
I use 0.5% potassium soap and 0.5% neem oil, mixed i.n warm water and use a pressure sprayer. I tried making sure to spray at beginning of lights off, but still am having this issue. Its directly related to the potassium soap/neem mixture but can't figure out why. I assume its too high pH on the leaves (especially new growth tops). I need to apply every 3ish days but it takes like 4-5 days for the damage to correct itself.





Member of the Month: Aug 2021
Maybe stop the potassium and just go with the Neem oil then alternate with Spinosad.

How are you spraying? You are an old pro and you know this stuff... but just as reminder move plant away from light fixtures, elevate plant then always spray leaf undersides first, get stems & stalk too, then finally spray the topside last. Undersides are where most critters live & lay eggs but if you spray the top side first then leaf undersides are hard to access because of leaves drooping down heavy with the weight of the spray on the foliage


Well-Known Member
I'm going to let her heal up and monitor from here. I plan to quit the potassium soap, but I will continue with neem as well as spinosad (Monterey Garden). The thrips are under control but with a 3 tent perpetual system, they will forever be around, so I'm thinking spinosad every 2 weeks until about week 4 of flower.

Bush Doctor 77

Well-Known Member
you could be blocking out zinc, iron and mag with potassium excess, my penny worth today :)
It really does not look like chemical burn. That tends to be blotchy, and not uniform. I'd stop with the K soap, and use Dove as a surfactant with the neem.


Well-Known Member
Update for you guys

She healed up and is chugging along just fine. I'm pretty sure it was the potassium soap. Now that they are healthy, I hit them with a low dose spinosad/neem mixture. I plan to use this as a preventative once a week through week 4 of flower. Its been about 18 hrs since the spray and no ill effects yet (although it normally takes about 48 hrs to really show up). If anything the leaves look better and more shiny after the spinosad/neem treatment. I'm very excited about this stuff. I'll update about both the plants reaction to it and its effectiveness as an insecticide.

As of now I'm using GardenSafe neem oil extract but I want to switch to Einstein Oil soon, as I've heard good things.



Well-Known Member
Thanks @BeanTownFan420 She was due for a defoliation and most of the larger leaves were the ones that were damaged so worked out. The plant in the original photos is actually the Dosidos in flowering so here's a few shots of her so you can see the damage/recovery.



Top Bottom