Leaf damage after potassium bicarbonate foliar

[Hipposcottamus1]

As the title says I applied a potassium bicarbonate spray last night as a second application in two weeks and woke up today with some weird burn on the leafs.

Spray was 1.5 L water, .5 L milk, 1 tbsp soap, 3 tbsp potassium bicarbonate

Wanted to hear some people's experience with anything that looks like this.

Thanks.

 

[Pacoson71]

Recipe I use was 1 gallon water 1/2 tsp castile soap and one tsp potassium bicarbonate.

1st time i mixed it too heavy and got what you have there. Nothing permanent.

 

[Willy B. Goode]

Same here, @Pacoson71, went with too hot a mix 1st time but had no problems long-term. Better to have a few spots on leaves than powdery mildew. That shit is the worst.

 

[Hipposcottamus1]

Same here, @Pacoson71, went with too hot a mix 1st time but had no problems long-term. Better to have a few spots on leaves than powdery mildew. That shit is the worst.

Thanks, pretty much what I was thinking too, just weird because this was a more diluted mix compared to my first spray a couple weeks ago.

 

[Rickywoo]

Recipe I use was 1 gallon water 1/2 tsp castile soap and one tsp potassium bicarbonate.

1st time i mixed it too heavy and got what you have there. Nothing permanent.

How well did this mixture work and how often did you have to spray? I gave my trouble spots a spray of this mixture last night…but it’s all still visible this morning.

 

[Somatek]

The damage could have shown up after the 2nd application from accumulated phytotoxicity, it does seem odd though.

I generally use neem oil and potassium bicarbonate together after reading papers about how a carrier oil increases the effectiveness of it. Using neem just means it's a general pesticide effective against pests and PM. In 1 liter of water I use 1/2 tbsp neem oil, 1tsp potassium bicarbonate and 1/2tsp of dr bronner's soap (mixing the neem oil and soap together to emulsify first, then diluting with warm water and adding the potassium bicarbonate).

 

[Rickywoo]

I left out neem oil, as I’m in flower. I was just curious as to how well that original mixture worked.

 

[Pacoson71]

That plant was doomed.... bud worms and PM overtook. Cut it a month early.
Still sitting in jars waiting for hashing.
That mix did work, I'd saturate an area under and stalks too.

 

[Charles U Farley]

Looks like everybody has their own recipe. I use one tablespoon of potassium bicarbonate, 1 tsp of castille soap, and one teaspoon of olive oil per gallon of water. Spray it on as a super fine mist.

Don't have to use it in the upstairs closet but using it in the downstairs tents because of bad PM. Seems to help tremendously with bud rot as well. Because of the high pH, it'll turn pistals red during flowering so if you're more concerned about how the buds look, then that might be a concern. I'm only interested in the psychic benefits and effects myself.

Initially tried two tablespoons of the potassium bicarb and it's scorched the shit out of the leaves where the solution pooled up and evaporated. Other than that minor problem, it's worked like a charm for me. Plants are in the first couple of weeks of flowering in 80° temps and 80% humidity and not a speck of white dust anywhere.

 

[Rickywoo]

This is what I was looking for, thanks for sharing your results. If I still see an issue I’ll up PC and I like the addition of olive oil. My grow is outdoors, so the humidity is very high through the night here.