What is the ratio of cinnamon to water ? As a fungicide spray.
It's going to depend on how large of a spray bottle you use. If it's a medium-sized bottle, maybe start out with a 1:4 ration of cinnamon to water, then keep adding a little at a time and stirring, for as long as it continues to dissolve. When you start seeing that it's not dissolving all the way, that should be enough. This article may help you: