What is in a Bag of Fertilizer?

I often forget that most folks do not understand what the numbers on a bag of fertilizer are there for or what they mean. This is understandable, as it can all be confusing if you are not familiar with fertilizers and fertilizer blends. Here is a quick guide to understanding the numbers and ingredients in a bag of fertilizer.

All fertilizer bags should contain 3 bold numbers. An example would be 12-12-12; this is a fertilizer we are all familiar with. The first 12 stands for the amount of nitrogen (N), in the bag of fertilizer, the second 12 is the amount of phosphate (P2O5), and the last 12 would be the amount of potassium (K). These are the three primary fertilizer nutrients required for plant growth. These are typically seen as nitrogen (N), phosphorus (P), and potassium (K). So, in this example a bag of triple 12 contains 12% nitrogen, 12% phosphate, and 12% potassium or potash. These 3 numbers are a national standard and must always be either on the bag or label, whether you are buying 50 lbs. or 5 tons of fertilizer.

In this example, triple 12 would be considered a blend that contains all three of the primary nutrients. To understand exactly how many pounds of each nutrient are in a 50lb bag of triple 12 you would multiply 50 by .12, which equals 6 lbs. of each nutrient. You are paying for 18 lbs. of nutrients in a 50 lb. bag of triple 12. This simple calculation holds true regardless of the fertilizer blend. This will also work if you are buying fertilizer by the ton. Let us take 1 ton of 24-10-10 as an example: You will multiply 2000 lbs. by .24 to get the amount of nitrogen per ton, and 2000 by .10 to get the amount of both phosphate and potash in a ton of this blend. In this example, you are getting 480 lbs. of N, 200 lbs. of P, and 200 lbs. of K in one ton.

How do you use these numbers? Let’s suppose your soil test indicated you will need 50 units of nitrogen and 20 units of both phosphate and potash per acre. If you apply 200 lbs. per acre of 24-10-10, you will be applying 48 units of N per acre and 20 units of both P and K per acre. This is a pretty simplistic example, but that is how it works.

If you are not confused enough now, next week we will talk about the importance of these three nutrients.

You are going to be getting a lot of exercise out there slinging fertilizer and doing various outside chores, so you might as well participate in the spring Walk Across Texas program and learn just how much your outdoor activities and other exercises are helping to keep you healthy. The spring Walk Across Texas program runs from March 18th through May 12th. Teams consist of 8 people, and you will need a Team Captain to create an individual team. To register for the eight‐week program, team captains can set-up their teams at: www. howdyhealth. org. and use league code: watL-240226-59688. Once the team captain has their team set-up, individuals can go in and register under their respective teams. If you would like more information, come by the office, or call us at (325)-356-2539.