There are numerous inorganic fertilizer sources on the market these days, too many to list, so I won't even try. The goal of this document is to help you understand the components of these fertilizers so you can make an informed decision when purchasing and applying them.

When you look at a bag of fertilizer, you will see 3 numbers. This is called the fertilizer's "analysis" and represents the percentage of nitrogen, phosphorus and potassium that is available from the bag of fertilizer. (Technically, it represents the percentage of N, P2O2 and K2O that is available, but for our purposes, nitrogen, phosphorus and potassium will do.) Using the fertilizer "5-10-5" as an example, the bag with this analysis will contain 5% nitrogen, 10% phosphorus and 5% potassium.

Now, you're probably thinking that 5 plus 10 plus 5 only adds to 20%, what's in the other 80% of the bag. Depending on the brand of fertilizer, the rest of the bag may contain some minor nutrients and filler material. The filler material allows us to apply the nutrients evenly across the area we want to fertilize. Without the filler material, we would overapply nutrients in some parts of the area and underapply in others. The filler material allows for a uniform application of the nutrients.

Understanding the fertilizer analysis is essential to purchasing and applying the right kind of fertilizer. Your choice of analysis should be based on the type of plants you are growing and the results from your soil test report.

For more information about inorganic fertilizers, visit the NCDA publication "A Homeowner's Guide to Fertilizer".

For information about fertilizer rules and regulations and some crop fertilizing suggestions, visit the North Carolina Agricultural Chemicals Manual Fertilizer Use section. (requires Adobe Acrobat Reader)

FERTILIZER ZONE HOME

For questions regarding Inorganic Fertilizers, e-mail me!

Date Created 9/14/98.
Revised 2/26/02.