Powdery mildew: Oops -- too strong of a baking soda mixture -- leaves burnt!!

Last night I applied the following baking soda mixture since the apple cider thing hasn't been working.

Well!

Today after work I came home to find the leaves burnt through!  OMG!  On the bright side, it certainly addressed the powdery mildew in those spots! 

This is what I used --
DON'T USE THIS RECIPE BEC IT'S TOO STRONG.
- 4 cups water
- 6 Tbsp baking soda
- 2 Tbsp vegetable oil


NEXT TIME, try putting at least twice as much water as this, see if that works better:
- 8 cups water
- 6 Tbsp baking soda
- 2 Tbsp vegetable oil