Sirflor 38

Sirflor AKA ‘Blue Chip’ is a slow-release fertilizer for turfgrass based on ureaformaldehyde. It gives a long-lasting source of N to encourage root growth and sustain growth.

  • One of the safest and longest-lasting slow-release N fertilizers.

  • Extensively researched.
  • SGN 125 means no mower pick up.
  • Ideal for golf fairways or sportsturf.
  • The N is from methylene urea (MU) and Ureaformaldehyde.

  • Over two-thirds is WIN.

  • Use of Sirflor reduces thatch build up.

  • Ureaformaldehyde encourages beneficial soil microorganisms.

  • Sirflor gives consistent feeding for 16 weeks or longer.

  • Less potential risk for leaching.

The release rate of ureaformaldehyde (UF) depends on the length of the UF chains. The release of N is temperature dependant and relies on the activity of soil microbes. The optimum temperature for microbe activity is around 21–32 °C.

Microbes break down methylene urea by the methylene urease enzyme. They feed on the carbon linking the urea molecules. Once the urea enzyme cleaves the urea molecules, they covert to ammonium and nitrate.


The Manufacture of ureaformaldehyde.

The diagram below shows how all synthetic organic nitrogen fertilisers use urea as their base material.

The manufacture of Sirflor involves the reaction of urea with formaldehyde plus a catalyst to form ureaform. These are white and contain around 38% nitrogen. Sirflor gets its distinct blue colour with the addition on a blue dye.

You can separate the UFs into several fractions based on their solubilities in cold (25°C) and hot (100°C) water. This gives rise to the terms Cold Water Soluble Nitrogen (CWSN), Hot Water Soluble Nitrogen (HWSN) and Hot Water Insoluble Nitrogen (HWIN).

The greater the percentage of long chain UF, the longer the release rate.


ureaformaldehyde manufacture


Reseach into Sirflor Blue Chip


Benefits of Sirflor Blue Chip

Sirflor gives a gradual & continuous N release for up to 16 weeks.

Key Features and Benefits

  • Provides a slow release of nitrogen over 16 weeks to maximise turf growth without surge growth.
  • It has an SGN of 125.
  • Nutrient release is not sensitive to water so ideal for areas of high rainfall/irrigation.
  • Sirflor improves N efficiency and reduces leaching
Product Form: Granular SGN 125.
Pack size: 25Kg.
N content: 38%.
Composition: Sirflor is a blue mini granule. It contains 12.5% N as water soluble urea formaldehyde and 25.5% N as water insoluble ureaformaldehyde.

Application Rate: 125Kg/Ha.

Sirflor 38 aka blue chip based on ureaformaldehyde

If you have questions or concerns about the use of Siflor38, please feel free to contact a sports turf consultant or turf agronomist.

Sirflor 38 Label

Sirflor 38 SDS