How to Read a Fertilizer Bag

Reading a fertilizer bag can be confusing, but it's an important skill to have to understand the product you're using and to make sure you’re applying the right fertilizer for your specific needs. If you're looking to apply fertilizer in Miami-Dade County, here is what you should know:

1. Check the nutrient ratio

The nutrient ratio is usually displayed on the front of the bag, in the form of three numbers, such as 10-0-10. These numbers represent the percentage by weight of nitrogen (N), phosphorus (P), and potassium (K), respectively, in the fertilizer. For example, a 10-0-10 fertilizer contains 10% nitrogen, 0% phosphorus, and 10% potassium. Different plants have different nutrient requirements, so it's important to choose a fertilizer with the appropriate nutrient ratio.

2. Look for a slow-release fertilizer

A slow-release fertilizer that releases nutrients over time, helps reduce the risk of runoff and pollution of nearby waterways. In Miami-Dade County, this is especially important. To determine the release rate, use this formula:

For example:

3. Check the label for other nutrients and additives

In addition to N, P, and K, some fertilizers contain nutrients, such as calcium, magnesium, and sulfur. If your soil is deficient in one of these nutrients, you may want to choose a fertilizer that contains it. Some fertilizers also contain additives, such as micronutrients, iron, or organic matter. These can be beneficial for certain plants, but it's important to understand what you're applying and why. These additional nutrients will be noted in the guaranteed analysis on the bag. In the example above, the fertilizer also contains sulfur, iron, and manganese.

4. Follow the instructions

Finally, it's important to follow the instructions on the fertilizer bag carefully. Over-fertilizing can be harmful to your plants and the environment, so make sure you apply the correct amount at the right time. It's also important to follow local regulations on fertilizer use to help protect nearby waterways and the environment. 

When choosing and applying fertilizer in Miami-Dade County, it's important to consider the nutrient ratio, choose a slow-release fertilizer, check for other nutrients and additives, and follow the instructions carefully. By doing so, you can help ensure healthy plants and a healthy environment.