1/10/2024 - By Mike Hess

Harrell’s POLYON® controlled-release fertilizer is the industry leader for delivering consistent, predictable, and dependable feeding, all the while reducing overall environmental impact, labor, and susceptibility to disease. POLYON® fertilizer is a unique polymer-coated urea that releases nutrients based on temperature. But how does this work?

How POLYON® Controlled-Release Fertilizer Works

Shortly after application, the polymer coating allows soil moisture in, which activates encapsulated nutrients. Over the next several weeks to months, the polymer coating slowly releases dissolved nutrients through diffusion in response to temperature. After the complete release of nutrients, the polymer coating microbially decomposes into naturally occurring soil elements, reducing overall environmental impact.

With Harrell’s proprietary POLYGRAPH® and CustoGraph® software, turf and horticulture managers can predict a formulation’s nutrient release from the initial application. Working alongside your Harrell's Rep to input all the necessary info about your fertilizer, region, and application time frame, our software can predict the timeline of nutrient release for your blend.

Controlled-Release Fertilizer: What Makes It Different?

Controlled-release technology, as seen in POLYON® fertilizer, is not a new concept. Many products and companies have used this technology to varying degrees for years, but none have done it quite like POLYON®. So, what makes our controlled-release technology different?

The success of POLYON® fertilizer’s controlled-release technology comes down to physical characteristics. Our Reactive Layer Coating and superior bonding properties create a tight adhesion between the coating and the inner nutrient substrate.

Having the coating of the fertilizer bonded to the nutrients in this way ensures:

1.       Predictable release – To ensure POLYON® fertilizer can go the distance, we test its performance at 86^o F.

2.       The durability of the prill – the tight seal of the reactive layer coating and superior bonding properties lead to overall prill durability and is key to predictable nutrient release.

3.       Consistency of results – POLYON® fertilizers durability can stand the toughest conditions, ensuring the nutrients are intact until the specific time they are planned for release, giving you consistent color and nutrients all season long.

Following application, POLYON® controlled-release fertilizer will normally begin its nutrient release within 1-2 weeks in favorable conditions. The release of POLYON® fertilizer is influenced by how thick the coating is. A thicker coating equals a longer release, especially at higher temperatures.

For POLYON® Controlled-Release Fertilizer, Temperature is Key

Temperature is key to the release of nutrients from POLYON® controlled-release fertilizer, making it different from traditional fertilizers which release on moisture. This reliance on a single predictable factor makes POLYON® fertilizer an extremely consistent, predictable, and dependable source of nutrients. However, you may be wondering how a sudden and extreme change in weather would affect POLYON’s nutrient release?

Florida, Michigan, and Arizona are just a few of the places POLYON is sold that often experience drastic weather changes. Therefore, POLYON® controlled-release fertilizer needs to be proven under extreme temperature swings. This way, our customers can be confident that it will perform exceedingly well even when the weather abruptly changes.

Thus, Harrell's and Virginia Tech University worked together to see what would happen with a dramatic increase in temperature using growth chambers. At the end of the experiment, Dr. Zhang and his team found turf fertilized with POLYON under high temperature and drought stress conditions showed better leaf color and higher chlorophyll content than turf fertilized with traditional fertilizer sources, with no real change to clipping production or root mass. Additionally, the research indicated turf may take up water and nutrients more efficiently following stress conditions when fertilized with POLYON.

Even under the most stressful weather conditions, POLYON® controlled-release fertilizer has been proven to deliver consistent and predictable results that you can rely on, year-round.

Custom-Blended POLYON® Controlled-Release Fertilizer

Every custom blended POLYON® fertilizer formulation begins with our most advanced POLYON® CRF (Controlled Release Fertilizer) and incorporates additional sources of nutrition, pertaining to your needs. Each essential nutrient of POLYON® fertilizer is completely customizable to your needs; if you need more nitrogen, phosphate, or potash, all of these can be added or subtracted from your custom blend. This is represented by the three numbers on the fertilizer label, which you can read more about here.

You also can add other products to your fertilizer formulation to further improve its efficacy. If you’re looking for a quick greening response from your turf, you could add some AMIDAS from Yara to the blend. Looking for a long-lasting potassium source? Try adding some extra POLYON® K to your mix.

Harrell’s has access to dozens of different raw materials as well as the option to sparge certain products on your batch of POLYON® fertilizer for added efficiency. Be sure to check with your Harrell’s rep to see which chemistries are registered in your state and take a look at these tips for effective sparged fertilizer preemergence programs.

Whether you work in golf, horticulture, sports turf, turf & landscape, or specialty agriculture, you have unique needs for what you’re growing. A custom fertilizer blend that meets your specific requirements can have a profound impact, not only on your turf, plants, and crops, but also on business inputs like labor cost.

Learn More About POLYON® Fertilizer with These Resources

In this video from Harrell's Director of Agronomy, Dr. Jeff Atkinson, we discuss how POLYON® is formulated, how the technology works, and so much more. Check it out to learn more!

Your Harrell's Rep is your best resource for choosing, customizing, monitoring, and predicting your POLYON® controlled-release fertilizer applications. Reach out to your Harrell's Rep today to get started and see for yourself how POLYON® fertilizer can help you. Don’t have one? Find your Harrell’s rep at https://harrells.com/Sales.