What are the numbers on the fertilizer bag?

If we're going to talk about lawn care, the first thing to cover is fertilizer. There are so many products available to the homeowner that the decision can be a bit overwhelming when standing in the lawn and garden center staring at 20 different bags. The question I get more often is the one posed in the title of this column. We'll cover that, and offer some choices when it comes to formulations that best suit your needs.

Typically, a three-numbered analysis will appear on the front of the bag that reads 16-16-16, or some other combination depending on the contents. Simply put, the three numbers are Nitrogen (N), Phosphorous (P) and Potassium (K), expressed in a percentage of the total. Typically, there are other ingredients contained in the bag, but only ratio of the first three appears on the main label. Other nutrients are listed in smaller print on the bag, including iron (Fe), sulfur (S) and calcium (Ca), just to name a few. These all play an important role in the health of your lawn, but to a lesser degree than the first three. Your selection will depend on time of year, condition of the lawn, new seeding or established lawn, or other factors.

Nitrogen is the most plentiful element in the Earth's atmosphere (almost 78 percent), and the first number on your fertilizer bag. Typically, this nutrient is the highest number, and for good reason. Nitrogen is the "grow" nutrient that is responsible for protein production and therefore growth of the plant. There are many different sources of nitrogen, but they all serve the same basic role in plant growth. The two primary classes of nitrogen are synthetic (man-made) and organic (carbon based). We will cover these sources in greater detail in a future column.

Phosphorous has gotten a bad rap in recent years as communities and state governments attempt to regulate its use and presence in fertilizers, detergents and soaps. I can assure you that without phosphorous uptake into plants, life on this Earth would not exist. Phosphorous is the nutrient responsible for the energy produced in photosynthesis (the factory within any plant), and fruit production. While it is true that phosphorous can be linked to algae blooms in waterways, it is incredibly stable in a turf situation and soils in general. It can only find its way to water if the soil it is found in goes with it.

Potassium (K) is like the bus that moves other nutrients to where they need to be within the plant. Adequate potassium is necessary for many of the processes within the plant. The highest quality fertilizers include sulfate of potash as their K source. It is best applied at higher ratios during spring and fall.

So what should you choose for general use? For spring, I'd recommend a product with a little more phosphorous than the rest of the year, in the ratio of 1:1:1 or 1:1:2. Summer, a ratio of 3:1:2 would be great, and fall a 1:1:2. Apply fertilizer in the spring as soon as you begin mowing. This is the critical time that plants need to the greatest amount of energy of the season.

If you have any questions or feedback contact Kevin Hicks at khicks@cdaresort.com.