Fertilization is key to maintaining a healthy lawn. Fertilizers supply essential nutrients to the turfgrass for proper growth and development. Fertilizer source, method of application and timing are important components to consider when developing a fertility plan for your home lawn.

Forms of fertilizer

Fertilizer comes in two forms, solid and liquid. Liquid fertilizers are fertilizers in which nutrients are either partially or completely dissolved. Liquid application is a popular method in commercially managed areas. Solid forms of fertilizers include soluble and granular fertilizers. Soluble fertilizers readily dissolve in water and are applied in a liquid. Granular fertilizers are composed of particles that range from 0.85 to 4.75 mm in size and applied dry. There are two major types of granular fertilizers:

Quick-release inorganic fertilizers are useful as a readily available source of nutrients. They are quickly dissolved by water through irrigation or rainfall and are available for turfgrass uptake for rapid growth. However, because they are so soluble, they are also more prone to movement and loss through leaching and runoff. Use of inorganic quick-release formulations should be applied at the proper rates, timing and environmental conditions.

Slow-release fertilizers have been developed to allow more even turfgrass growth and reduced application frequency. These nutrients are composed of slowly soluble forms or coated granules to slow nutrient release. Slowly soluble fertilizers and coated fertilizers depend on soil moisture and temperature to release nutrients. In the case of slowly soluble forms, nutrient release is generally due to increased microbial breakdown, whereas coated fertilizer release of nutrients is the result of the coating technology. Controlled release of nutrients over a period of time, sometimes for several months, requires fewer applications and can minimize nutrient losses.

When to apply

Always have your soil tested before applying any fertilizer and follow soil test recommendations for proper fertility. It is important to consider irrigation timing or potential rainfall because water can affect the release of nutrients, rate of leaching and runoff. In general, fertilizer is more effectively used by turfgrass if it is applied more frequently in small amounts as opposed to being applied less frequently in large amounts. Most fertilizers should be applied from midspring to midsummer when turfgrass is actively growing. Never apply more than 1 pound of nitrogen per 1,000 square feet for each application.

How to read a fertilizer label

Fertilizer is a compound that contains at least one essential nutrient for plant growth. A fertilizer label displays the manufacturer’s information, nutrient sources and nutrient amounts. The fertilizer grade, or analysis, is composed of three numbers that represent nitrogen (N), phosphorus (P₂O₅) and potassium (K₂O). The amount of nitrogen to phosphorus and potassium forms a ratio. The ratio of nitrogen, phosphorus and potassium is known as a fertilizer ratio (e.g., 18-24-12 is a 3:4:2). If fertilizer applications are made based on nitrogen rate, it allows one to easily calculate the application rates of phosphorus and potassium. All nutrients are listed as a percentage by weight of the fertilizer on the label. In addition, the label will list the formulations of the nutrients (the source of nutrients) as well as the amount of a nutrient that is water-soluble or readily available to the plant.

Download here: Louisiana Home Lawn Series: Fertilizer Basics 3624-FFF