Turf[TECH]Report: CRN: Controlled Release Nitrogen - What you don't know could BURN your turf!

November 7, 2018

WHAT IS CONTROLLED RELEASE NITROGEN?
Controlled Release Nitrogen (CRN) consists of uniform granules (usually urea-based) designed to release nitrogen into the soil over an extended time period. This is as opposed to straight urea, which is considered to be ‘immediately available nitrogen.’ The mechanism for controlling the release of nitrogen is a physical barrier. Controlled release nitrogen is typically encapsulated by a combination one or more layers of polymer, sulfur and wax. These layers work in tandem to control the rate that water enters the granule, then control the rate at which dissolved urea nitrogen leaves the granule.  
                                                                                           
WHAT COATING TECHNOLOGIES ARE AVAILABLE AND HOW DO THEY COMPARE? 
Sulfur Coated Urea (SCU) was the first type of CRN to hit the market nearly 50 years ago. Sulfur is very effective at repelling water, however sulfur coatings are extremely brittle. The Sulfur coating fractures allowing water to find its way inside, the granule expands, further fracturing the sulfur coating. Once this occurs, dissolved urea flows out quickly. SCU works on the premise that some granules will take longer to fracture and release their nutrients than others. Over the course of time, this “mix” of release times results in continuous nitrogen feeding until the last granules have fractured. Most products have a wax that is applied atop the sulfur layer to slow the rate of nitrogen release by protecting the Sulfur layer. 

Temperature can also affect CRN granules coated with wax because waxes are slowly broken down by soil microbes (microbes are more active in warmer soil temperatures). In recent years, SCU has been enhanced by hardeners and or polymers that further protect the inner brittle sulfur layer or protect the water from reaching the inner granular, effectively stabilizing the release curves of SCUs. These enhanced SCU base products which combine polymers are often referred to as Polymer coated sulfur coated ureas. XCU® is an example of an advanced SCU or PCSCU.  

Polymer (or Plastic) Coated Urea (PCU) generally has longer and more stable release properties vs most SCU based products. PCU granules can consist of one or more polymer layers allowing for greater extended release times. Polymer coatings are less susceptible to fracturing (abrasion) during transport than sulfur coatings thus their release times are more consistent. Through osmosis, water diffuses through the polymer layer and slowly dissolves the urea core. Over the course of many weeks or months, urea slowly dissolves through the polymer layer providing an even, controlled distribution of nitrogen over a large portion of the growing season. Once the urea has been depleted, the thin polymer shell is biodegraded naturally by soil microbes, making PCU technology very efficient and environmentally friendly. DURATION® is an example of an advanced PCU.
 
HOW TO READ A CRN LABEL
Every fertilizer label contains an N-P-K analysis and a derived-from statement. The analysis shows the percent by weight of each element inside a fertilizer bag. The derived-from statement shows what raw ingredients those elements are derived from. In addition to an analysis and a derived-from statement, every label must also show the guaranteed percent of “slowly available nitrogen,” and the source of that nitrogen.  

Take for example TCS Growstar’s 29-0-4 Professional Lawn Fertilizer + Iron. This blend contains both Urea and Polymer Sulfur-Coated Urea (PSCU). 29% of the entire bag by weight is nitrogen. 9.1% of the entire bag by weight is nitrogen derived from PSCU. That means that 31.3% of the total nitrogen is CRN (from PSCU) and 68.7% of the total nitrogen is urea.  

A guaranteed analysis of a fertilizer is shown

WHAT IS A DISSOLUTION RATE?
Every controlled-release fertilizer has a dissolution rate associated with it. The dissolution rate refers to how much dissolved urea has been depleted (or released) over a time period. In general, the industry goal is to manufacture CRNs with minimal to no release in the first 3 days, because urea is providing the Nitrogen during the first 3 days. Then from day 4 to the desired days of release (typically 45,90,120,180) a consistent release on nitrogen each week (see chart 1) is optimal, however in reality most dissolution rate curves varying by CRN type. CRN products can last anywhere from 30 days to up to 180 days. In general, 30-day products have thinner coatings, so they deplete their nitrogen faster. 180-day products have thicker and multiple coatings, often consisting mainly of polymer. More coatings and or thicker coatings translate to products with longer dissolution rates. Not surprisingly, these products take more time to manufacture and use more coating components, hence they drive a premium price point.

A graph showing the difference between urea and goal crn

Urea vs. GOAL CRN (chart 1):  Note that in this chart, urea is depleted within the first 3 days of being applied to the ground.  This is why manufacturers strive to create CRN products that don’t release any nitrogen until shortly after straight urea has been depleted.

A graph showing the first generation scu vs improved scu.

1stGeneration SCU vs. Improved SCU (chart 2): Note that 1stGeneration SCU products typically release up to 30% of their nitrogen within the first few days; this is undesirable as most fertilizer blends already have straight urea in them.  Improved SCU products demonstrate a nearly 20% reduction in nitrogen release in the first few days; this is desirable.  Why pay a premium for CRNs that behave like straight urea within the first few days of their application?

A graph showing basic pcu vs improved pcu

Basic PCU vs. Improved PCU (chart 3): Note that with improved PCU, nitrogen release is delayed within the first week (this is desirable), and that the overall release curve is much straighter than that of basic PCU. Many improved PCU products now last well beyond 90 days with consistent and predictable nitrogen release week to week.

 THE EVOLUTION OF CRNS OVER TIME  Take a look at the dissolution rate curves in the graph above. These curves do not represent specific CRN products, but rather demonstrate the evolution of classes of CRN products over time. First, note that straight urea (46-0-0) releases nearly all of its nitrogen within 3 days under normal conditions (chart 1). Urea is the best source of nitrogen on a cost per ton basis, hence urea is the base raw ingredient for nearly all CRN products.


Next, look at (chart 2) basic SCU (invented in the late 1960s). Note that basic SCU releases nearly 30% of its nitrogen within the first day or two. Its release curve mimics a standard logarithmic curve, meaning compared to other CRNs, it releases more of its nitrogen earlier in the curve. Given this challenge (too much nitrogen release within the first few days), manufacturers and agronomists were determined to reduce this initial nitrogen load into the ground. This led to the development of polymer coated urea (PCU) several decades later. In addition to quelling the early nitrogen release problem associated with first generation SCU, PCU also brought straighter, more consistent release curves to the industry (chart 3). Today’s improved PCU products have release curves that mimic a shape of a hockey stick, resulting in more gentle transitional nitrogen feeding for turf. Improved PCU products have also been engineered to reduce lock-off issues, and last longer in the field.

 

Last, the higher costs associated with components and manufacturing improved PCU products has led to the development of improved or “enhanced” SCU products. Improved SCU uses hardeners and or polymers and or waxes to mitigate the early nitrogen release issues associated with 1stgeneration SCU products. Improved SCU products are also more resistant to abrasion and have longer release windows. Some improved SCU products now last as long as 90 days in the field. 

  

 HOW DO I CHOSE THE RIGHT CRN FOR ME?

Choosing the right CRN comes from an understanding the dissolution rate (or release curve profile) of each CRN, and then deciding which CRN gives you the nitrogen you need when you need it. For example, an applicator who only likes to drop fertilizer in the spring may want to pay a premium for a 180-day CRN, that way he or she only has to fertilizer once per year. In most cool season grass climates, a 180-day product will make it through most of the growing season (year to year variations in weather will affect the performance of a 180-day product). Conversely, a lawn care business might prefer a 45-day product such as XCU, due to sporadic weather conditions, financial factors, specific agronomic / control programs, etc. This isn’t necessarily a bad thing for lawn health either; more nitrogen is making into soil and being taken up by the plant per year than dropping a 180-day product only once per year. You should pick your CRN product based on how it fits into your turf maintenance program. For example, if you only fertilizer twice per year, two 90-day products might be right for your situation. If you’re a golf course superintendent, you might prefer to “spoon-feed” your turf, which means you might want to use 30-day products 5-8 times per year. It all depends on your climate and the nature of your turf maintenance program.

  

 WHAT ARE THE EFFECTS OF APPLYING LOW-QUALITY CRN PRODUCTS TO TURF?

The whole concept behind CRN products is that they release nitrogen slowly and evenly over time. Low quality coatings are more susceptible to fracturing through abrasion (the colliding of CRN granules against each other during storage and transport). This is why most CRN products guarantee up to about 90% of their slow-release integrity on the bag. (What this means is, if you had a 50 LB bag of pure 39-0-0 SCU, about 10% of the bag would be considered ‘immediate release’ due to the fracturing of about 10% of the SCU granules during storage and transport. Fractured coatings are considered ‘compromised’ and are treated the same as straight urea from a labeling standpoint.) Low-quality CRN products run the risk of behaving like straight urea, which means they have the potential to burn or even kill a lawn. Before purchasing any CRN, ask for dissolution rate data and don’t hesitate to dig into that product’s industry reputation. 


For professional fertilizers, humic and AMP-XC™ enriched products available, please visit TurfCare’s online Product Catalog.
 
For green industry professionals or others interested in ordering Turfcare products, please contact our Customer Service to find a distributor near you.

The TURFReport Highlights:

Additional Articles and Insights

January 30, 2026
White Plains, NY – January 30, 2026 – Interoceanic Corporation (“IOC”) announced today that its affiliate Spring Valley USA (Spring Valley) , has acquired the blending and packaging assets and business of Turf Care Supply, LLC, a leading manufacturer and blender of turf and ornamental fertilizers as well as ice melt. The combination of Spring Valley and Turf Care Supply’s blending business, forms one of the largest independent lawn and garden fertilizer platforms in North America. The integrated business will have approximately 250 employees and will operate eight manufacturing and blending facilities across seven states, enabling coast-to-coast coverage of customers. By uniting two highly complementary companies, this acquisition creates a world-class turf & ornamental supply company positioned to deliver enhanced value to both professional and retail customers. “This acquisition is a transformative step for our organization,” said Elio Mazzella , President of IOC and Spring Valley. “By bringing Turf Care Supply into the IOC family, we are significantly expanding our reach and capabilities in serving the lawn and garden industry. The combined company will have an unrivaled production footprint and product portfolio, which means we can offer our customers faster service, greater efficiency, and innovative solutions on a national scale. Our goal is to build a world-class platform that blends the strengths of both businesses – the supply chain efficiencies of the combined business and the family-business values – will drive growth for our customers and vendor partners.” With the closing of the transaction, Turf Care Supply, LLC will be renamed Allied Nutrients and continue to manufacture leading enhanced efficiency fertilizers (“EEF”) out of its Martins Ferry, Ohio facility. Mark Mangan, President of Allied Nutrients, commented, “we want to thank our long-time employees that will be joining the IOC family and wish them well. We have known the IOC team for many years and believe this will be a great home. At the same time, we are excited for our remaining employees as we focus our resources and efforts on providing the best EEF solutions to the turf and ornamental market.” With this acquisition, the combined company now operates manufacturing facilities in Wisconsin, Ohio, Texas, Florida, Massachusetts, Tennessee, and Oklahoma, giving it the ability to blend and package fertilizer products and ice melt closer to customers in every major region. Turf Care Supply’s sites in Hatfield (MA), Sebring (FL), Cleveland (TN), and Catoosa (OK) will join Spring Valley’s existing plants in Jackson (WI), Fostoria (OH), Greenville (TX), and Longwood (FL). This expanded footprint significantly reduces transit times and enhances supply reliability for our customers. Maintaining strong customer relationships during and after the integration is a top priority. “All of our customers will continue to receive the outstanding service and product quality they expect, now with the added benefit of a truly national production network,” Mazzella added. Each major customer will be supported by an expanded team dedicated to ensuring a seamless transition and ongoing success. Strategically, the merger of Spring Valley and Turf Care Supply unlocks significant commercial synergies that will benefit both our customers and vendor partners. Together, the company will offer the most comprehensive product portfolio in the industry. “This combination is about building a platform that is perfectly suited to support our customers growth,” said Mazzella. “By combining our R&D and product development efforts, we intend to bring new, high-value solutions to market that neither company could have achieved alone.” The integration of the two businesses is already underway, with a focus on maintaining operational continuity and exceptional customer service throughout the spring season. The company also emphasized that all Turf Care Supply employees are being welcomed into the organization, and that the combined workforce will play a crucial role in driving the business forward. “This is an exciting moment for all of us. By uniting two great teams, we’re creating a stronger company with a shared commitment to our customers’ and vendors success, ” Mazzella noted. About Interoceanic Corporation (IOC): Based in White Plains, NY, IOC is a diversified family-owned company specializing in the production, marketing, and distribution of fertilizer and industrial chemical products. Other notable affiliates of IOC are PCI Nitrogen, Columbia River Nitrogen and EM² Enterprises. With this transaction, the group of businesses consist of over 600 employees. IOC’s family values, entrepreneurial spirit, and supply chain expertise have driven its growth from a regional fertilizer distributor into an international platform that provides reliable, high-quality products. About Allied Nutrients: Based in Brunswick, OH, Allied Nutrients specializes in providing enhanced efficiency fertilizers that support turfgrass and ornamental plant health. Through world-class manufacturing and research and development, the company offers a comprehensive portfolio of products, including SCU, PCU, PCSCU, reacted slow-release nitrogen, and urease inhibitors. These solutions are marketed under leading brands, such as XCU, TTRU, UFLEXX, UMAXX, Nutralene, and Nitroform. 
The hidden cost of filler: how to maximize your fertilizer ROI. Shows hand holding filler .
January 22, 2026
Want to maximize your ROI and turf health? Ditch the filler and replace your blends with Enhanced Efficiency Fertilizers (EEFs), Micro packs, Soil Amendments, or organic materials. These alternatives can reduce your seasonal application of bags, reduce overall material cost and deliver better results!
A large fertilizer manufacturing facility
April 18, 2025
Turf Care Supply, LLC, a portfolio company of Platte River Equity, has officially acquired Beaty Fertilizer, the industry respected Tennessee-based manufacturer and blender of custom granular and liquid fertilizers, as well as combination products. This strategic move expands Turf Care’s manufacturing footprint, adds new product capabilities, and enhances overall production capacity.
grubs on dirt
April 18, 2025
Root out Grubs, Before they Attack Yours!
October 9, 2024
Platte River Equity Portfolio Company Turf Care Supply, LLC Acquires Agri-Nutrients, Inc.
October 4, 2024
Dear Valued Industry Partners and Customers, We are pleased to announce that Turf Care Supply, LLC has acquired Agri-Nutrients, Inc. (October 1, 2024) a respected manufacturer in the turf and ornamental fertilizer industry. This acquisition marks a significant step forward in our commitment to providing you with an expanded range of innovative products, services, and industry expertise, all designed to support your business’s continued growth and success. As a valued partner or customer, you will benefit from enhanced service capabilities and an extended geographic reach, thanks to Agri-Nutrients, Inc.’s strategic facility located in the Port of Catoosa, Oklahoma. With this established presence in the Southwest and Western markets, Turf Care Supply, LLC’s expanded operational footprint will allow us to serve a broader region with greater efficiency, delivering even stronger support to help drive your business forward. We are dedicated to ensuring a seamless transition while maintaining the high standards of service you expect. If you have any questions or would like to explore how this new location can enhance your operations, please feel free to contact your account manager or our customer service team. Thank you for your continued trust in Turf Care Supply, LLC . We look forward to partnering with you as we grow together and continue supporting your success. Sincerely, Mark ManganPresidentTurf Care Supply, LLC
A forklift is sitting in a garage next to another forklift.
September 28, 2023
With a focus on providing sustainable manufacturing and reducing carbon emissions, Turf Care Supply has embraced the electric power market with the latest mobile equipment upgrades. Completed in June 2023, TCS received all deliveries of electric forklifts to all three manufacturing facilities, including Hatfield, MA, Martins Ferry, OH and Sebring, FL.
A person is holding a safety data sheet in front of bottles
July 19, 2023
When handling fertilizers and pesticide it is important to follow suggested guidelines and prioritize safety to protect yourself, others, and reduce environmental impact. Here are some general measures to follow: 1.Read and Follow Instructions: Carefully read and understand the product labels, safety data sheets (SDS), and any accompanying instructions provided by the manufacturer. Follow all recommended guidelines, precautions, and application rates.
A tur care advertisement for fertilizer application tips
June 22, 2023
It’s common knowledge that applying too much fertilizer containing high percentages of readily available nitrogen and water soluble nutrients can result in burn damage to plants, but did you know that damage can still occur even if your application rate is correct? Applying the right product at the right rate, but at the WRONG time can have disastrous consequences.
Show More
January 30, 2026
White Plains, NY – January 30, 2026 – Interoceanic Corporation (“IOC”) announced today that its affiliate Spring Valley USA (Spring Valley) , has acquired the blending and packaging assets and business of Turf Care Supply, LLC, a leading manufacturer and blender of turf and ornamental fertilizers as well as ice melt. The combination of Spring Valley and Turf Care Supply’s blending business, forms one of the largest independent lawn and garden fertilizer platforms in North America. The integrated business will have approximately 250 employees and will operate eight manufacturing and blending facilities across seven states, enabling coast-to-coast coverage of customers. By uniting two highly complementary companies, this acquisition creates a world-class turf & ornamental supply company positioned to deliver enhanced value to both professional and retail customers. “This acquisition is a transformative step for our organization,” said Elio Mazzella , President of IOC and Spring Valley. “By bringing Turf Care Supply into the IOC family, we are significantly expanding our reach and capabilities in serving the lawn and garden industry. The combined company will have an unrivaled production footprint and product portfolio, which means we can offer our customers faster service, greater efficiency, and innovative solutions on a national scale. Our goal is to build a world-class platform that blends the strengths of both businesses – the supply chain efficiencies of the combined business and the family-business values – will drive growth for our customers and vendor partners.” With the closing of the transaction, Turf Care Supply, LLC will be renamed Allied Nutrients and continue to manufacture leading enhanced efficiency fertilizers (“EEF”) out of its Martins Ferry, Ohio facility. Mark Mangan, President of Allied Nutrients, commented, “we want to thank our long-time employees that will be joining the IOC family and wish them well. We have known the IOC team for many years and believe this will be a great home. At the same time, we are excited for our remaining employees as we focus our resources and efforts on providing the best EEF solutions to the turf and ornamental market.” With this acquisition, the combined company now operates manufacturing facilities in Wisconsin, Ohio, Texas, Florida, Massachusetts, Tennessee, and Oklahoma, giving it the ability to blend and package fertilizer products and ice melt closer to customers in every major region. Turf Care Supply’s sites in Hatfield (MA), Sebring (FL), Cleveland (TN), and Catoosa (OK) will join Spring Valley’s existing plants in Jackson (WI), Fostoria (OH), Greenville (TX), and Longwood (FL). This expanded footprint significantly reduces transit times and enhances supply reliability for our customers. Maintaining strong customer relationships during and after the integration is a top priority. “All of our customers will continue to receive the outstanding service and product quality they expect, now with the added benefit of a truly national production network,” Mazzella added. Each major customer will be supported by an expanded team dedicated to ensuring a seamless transition and ongoing success. Strategically, the merger of Spring Valley and Turf Care Supply unlocks significant commercial synergies that will benefit both our customers and vendor partners. Together, the company will offer the most comprehensive product portfolio in the industry. “This combination is about building a platform that is perfectly suited to support our customers growth,” said Mazzella. “By combining our R&D and product development efforts, we intend to bring new, high-value solutions to market that neither company could have achieved alone.” The integration of the two businesses is already underway, with a focus on maintaining operational continuity and exceptional customer service throughout the spring season. The company also emphasized that all Turf Care Supply employees are being welcomed into the organization, and that the combined workforce will play a crucial role in driving the business forward. “This is an exciting moment for all of us. By uniting two great teams, we’re creating a stronger company with a shared commitment to our customers’ and vendors success, ” Mazzella noted. About Interoceanic Corporation (IOC): Based in White Plains, NY, IOC is a diversified family-owned company specializing in the production, marketing, and distribution of fertilizer and industrial chemical products. Other notable affiliates of IOC are PCI Nitrogen, Columbia River Nitrogen and EM² Enterprises. With this transaction, the group of businesses consist of over 600 employees. IOC’s family values, entrepreneurial spirit, and supply chain expertise have driven its growth from a regional fertilizer distributor into an international platform that provides reliable, high-quality products. About Allied Nutrients: Based in Brunswick, OH, Allied Nutrients specializes in providing enhanced efficiency fertilizers that support turfgrass and ornamental plant health. Through world-class manufacturing and research and development, the company offers a comprehensive portfolio of products, including SCU, PCU, PCSCU, reacted slow-release nitrogen, and urease inhibitors. These solutions are marketed under leading brands, such as XCU, TTRU, UFLEXX, UMAXX, Nutralene, and Nitroform. 
The hidden cost of filler: how to maximize your fertilizer ROI. Shows hand holding filler .
January 22, 2026
Want to maximize your ROI and turf health? Ditch the filler and replace your blends with Enhanced Efficiency Fertilizers (EEFs), Micro packs, Soil Amendments, or organic materials. These alternatives can reduce your seasonal application of bags, reduce overall material cost and deliver better results!
A large fertilizer manufacturing facility
April 18, 2025
Turf Care Supply, LLC, a portfolio company of Platte River Equity, has officially acquired Beaty Fertilizer, the industry respected Tennessee-based manufacturer and blender of custom granular and liquid fertilizers, as well as combination products. This strategic move expands Turf Care’s manufacturing footprint, adds new product capabilities, and enhances overall production capacity.
grubs on dirt
April 18, 2025
Root out Grubs, Before they Attack Yours!
October 9, 2024
Platte River Equity Portfolio Company Turf Care Supply, LLC Acquires Agri-Nutrients, Inc.
October 4, 2024
Dear Valued Industry Partners and Customers, We are pleased to announce that Turf Care Supply, LLC has acquired Agri-Nutrients, Inc. (October 1, 2024) a respected manufacturer in the turf and ornamental fertilizer industry. This acquisition marks a significant step forward in our commitment to providing you with an expanded range of innovative products, services, and industry expertise, all designed to support your business’s continued growth and success. As a valued partner or customer, you will benefit from enhanced service capabilities and an extended geographic reach, thanks to Agri-Nutrients, Inc.’s strategic facility located in the Port of Catoosa, Oklahoma. With this established presence in the Southwest and Western markets, Turf Care Supply, LLC’s expanded operational footprint will allow us to serve a broader region with greater efficiency, delivering even stronger support to help drive your business forward. We are dedicated to ensuring a seamless transition while maintaining the high standards of service you expect. If you have any questions or would like to explore how this new location can enhance your operations, please feel free to contact your account manager or our customer service team. Thank you for your continued trust in Turf Care Supply, LLC . We look forward to partnering with you as we grow together and continue supporting your success. Sincerely, Mark ManganPresidentTurf Care Supply, LLC
A forklift is sitting in a garage next to another forklift.
September 28, 2023
With a focus on providing sustainable manufacturing and reducing carbon emissions, Turf Care Supply has embraced the electric power market with the latest mobile equipment upgrades. Completed in June 2023, TCS received all deliveries of electric forklifts to all three manufacturing facilities, including Hatfield, MA, Martins Ferry, OH and Sebring, FL.
A person is holding a safety data sheet in front of bottles
July 19, 2023
When handling fertilizers and pesticide it is important to follow suggested guidelines and prioritize safety to protect yourself, others, and reduce environmental impact. Here are some general measures to follow: 1.Read and Follow Instructions: Carefully read and understand the product labels, safety data sheets (SDS), and any accompanying instructions provided by the manufacturer. Follow all recommended guidelines, precautions, and application rates.
Show More