Gardeners normally talk about “teaspoons” of fertilizer when they make up fertilizer solutions, which leads to all kinds of confusion and misuse of fertilizer. Some of you are using too little, while others use way too much. On the other hand, horticultural professionals don’t make these mistakes because they talk about PPM values instead.
It’s time gardeners change their habits. Start using Parts Per Million (PPM) units instead of teaspoons in your discussions. This will improve online information and reduce your fertilizer mistakes. I discussed the reasons for doing this, along with several examples, in Calculating the PPM of Nitrogen in Your Fertilizer.
To help you use ppm values, I have created this simple-to-use Fertilizer PPM Calculator, which shows you how much fertilizer to use to make up a required ppm solution. It works for both metric and imperial units, and can be used for both solid and liquid fertilizers.

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