Is wood vinegar good for orchids?

We recommend against using any vinegar on orchids. That’s because vinegar is an acid, and orchids are sensitive to changes in pH. If you must use vinegar, make sure it is diluted with water first; wood vinegar can be highly toxic to plants if used in large quantities. Whether you want to provide your orchid with food, or deter pests, there are better ways to do it e.g. with fertilizer or cinnamon.