Learn the science behind control-release and enhanced-efficiency fertilizers

June 12, 2023 -  By
Spreading fertilizer (Photo: BanksPhotos/iStock / Getty Images Plus/Getty Images)

(Photo: BanksPhotos/iStock / Getty Images Plus/Getty Images)

As spring shifts to summer, lawn care operators (LCOs) look to maximize their fertilizer applications. Over the past few years, the industry has embraced controlled-release and enhanced-efficiency fertilizers — reducing labor costs and saving time. Ben Pease, Ph.D., turfgrass agronomist with The Andersons, says these fertilizers help LCOs save on applications.

“The LCO doesn’t always have to be there as these fertilizers allow for much more even feeding for the turfgrass,” he says. “Money and time are saved by lowering labor costs while still maintaining a quality lawn.”

Pease says these fertilizers can boost color and growth with balanced feeding. These fertilizers also offer LCOs the ability to apply control products at once.

“There (may be) herbicides and insecticides incorporated, so you can do two things at once with a granular application,” he says.

“These fertilizers are so versatile,” John Fowler, vice president of sales for Anuvia Plant Nutrient’s turf division, says. “They are a great delivery system for preemergent chemistry and insecticides, sometimes at the same time.”

A versatile option

Controlled-release fertilizers (CRF) are granular fertilizers that gradually release nutrients into the soil over time. While traditional fertilizers typically last one or two weeks, CRFs last between 60 and 180 days.

The controlled element of a CRF is the release of nutrients into the soil. According to Pease, the nutrients released in these fertilizers range between 20 and 100 percent slower than in traditional fertilizers.

LCOs may choose different types of CRFs — with a different rate of release or a CRF with nitrogen, potassium or phosphorus — depending on the needs of the turf. Most controlled releases include sulfur-coated urea, explains Pease. He says CRFs can use chemically treated urea, such as methylene and some use inorganic and natural sources of nitrogen.


Enhanced-efficiency fertilizers (EEFs) are another form of slow-release fertilizer. They decrease nutrient losses while increasing nutrient availability for the turf. EEFs also regulate the release of nitrogen for more effective nutrient delivery.

Different types of EEFs include urease and nitrification inhibitors, which can be homogeneously distributed or coated with urea. In addition, there are slow-release nitrogen fertilizers, such as compost and manure.

John Perry, founder and president of Greene County Fertilizer Co., says LCOs should consider late spring and early summer as the most effective times to apply these fertilizers.

One restriction around the use of these fertilizers is nutrient blackout periods in certain cities and states. This is the time frame where LCOs cannot apply fertilizers containing nitrogen or phosphorus — typically from early June through late September and usually in tropical or subtropical climates.

Maintenance matters

Still, even with fertilizer innovations, lawn maintenance still requires routine checks, Perry says.

Another element LCOs should remember when using CRFs and EEFs is to change the spreader calibration settings depending on the product.

To make the most of these fertilizers, remember to work with your local distributor representative, Fowler says.

“Distributors are valuable resources,” he says. “They see many different types and sizes of fertilizers and have a great deal of experience solving problems.”

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