That's an old-wives tale and if true, my outdoor garden plants should be covered with burn marks.Wait it out.. afaik you never want to spray during lights on or day time (if outdoors) or you risk burning your plant as the water magnifies the light/sun.
I sprayed my plants with potassium bicarbonate early this morning and now most leaves are burned and bud hairs turned brown. I still have a few weeks until I harvest. Is there anything I can do to save the plants and buds?