Feeding your lawn is part of maintaining a healthy lawn. To properly feed, you need to know how to decode and interpret a lawn fertilizer label. Applying the right fertilizer in the correct amount will help you grow a beautiful and healthy lawn. If you give your lawn too much of the wrong type of fertilizer (or even too much of the right fertilizer), you risk polluting your water source, and killing your grass!



The Label is the Law

The first thing that commercial growers learn is that they must read the label on any chemical they wish to apply. The label on fertilizers, pesticides and herbicides contains all of the information needed to calculate the proper dose, as well as instructions for protective equipment needed to apply the chemical. Home gardeners also need to read the label. Fertilizers are chemicals, too, and can cause serious damage to plants and people if not handled carefully. This is one instance where you really do need to read the directions! (Sorry guys!)

Information on the Label

The fertilizer label will have information about when to apply the fertilizer, how much to apply per area, what equipment you will need, and how to care for the lawn after applying the fertilizer. The label will also have information about what is contained in the fertilizer. All chemicals have active ingredients and inactive ingredients. The active ingredients are the parts of the chemical that produces an affect. Inactive ingredients do not affect the activity of the chemical, but aid in dispersing it, applying it, or measuring it.

N-P-K What?

For most lawn fertilizers, the prominent piece of information on the label is the ratio of Nitrogen (N), Phosphorous (P) and Potassium (K). You might see a fertilizer that is 30-30-30 or 10-10-10. Those two fertilizers would have the same ratio of each nutrient. A fertilizer that is 5-10-5, or 20-40-20 has twice as much Phosphorous as Nitrogen and Potassium.

Depending upon the time of year you are applying fertilizer, results from your soil test, and your species of grass, you will need to select fertilizers with different ratios. A soil test will tell you if you have enough Phosphorous and Potassium. Soil tests cannot test for Nitrogen because it moves quickly in the soil, and the readings change from day to day.

Nitrogen, Phosphorous and Potassium all help plants grow by performing different functions in plants. That is why depending on the grass species, time of year and soil test results, you will need fertilizers with varying ratios.

Slow or Fast Fertilizer

The lawn fertilizer label will tell whether the fertilizer is a slow-release or quick release fertilizer. Many fertilizers contain some slow release nitrogen and some quick release nitrogen along with the other nutrients. Slow-release fertilizers are less likely to do damage to the lawn if they are applied incorrectly.

Amount of Fertilizer Needed

Fertilizer labels will also tell you how much fertilizer to apply to your lawn. When fertilizing in the fall for optimum root growth, you will apply more fertilizer than in the spring or summer. The fall fertilizer application allows plants to grow healthy root systems and prepare for spring growth. Summer requires less fertilizer, and applying too much can burn the plants.

Understanding how to read a fertilizer label will save you time and money, and will help you grow a lush, green lawn.