I have a bottle that I fill up regularly, so up to the mark with water, then the rest with ammonia. So, that is not much help, but I started using it on my hostas for slugs, and the best I recall there was a very wide variance in the ratios recommended. so by trial and error I experimented until I got about a weak of a solution that seemed effective, somewhere around 12 parts water to 1 part ammonia would be close.
