Controlled confusion

Controlled confusion

The Scotts Advisory Service has fielded a number of pleas for help this season regarding controlled release fertilizer release rates. With more and more products on the market, it's important to understand what the terminology means before choosing a formulation. We asked Technical Manager Simon Barnaby to explain: Controlled release fertilizer products like Sierrablen can play an enormous role in turf management. With the right one, you can be looking at accurate, safe and reliable nutrient provision over a long period - giving you better turf growth and colour, enhanced health and resilience and massive savings in application costs.

Nutrient release longevities are governed by temperature, with the products lasting longer at lower temperatures, but at a lower delivery rate. Basically, the colder it is, the lower the rate of nutrient release and, therefore, the longer the reservoir in the granule will last. While this is the fundamental benefit of the products, inappropriate declarations can mislead the unwary. The longevity of all Sierrablen formulations is declared at 21ºC.The Sierrablen 28:5:5 formulation, for example, is a 5-6 month product at this temperature. A competitor 30:8:8 5-6 month product may on the face of it appear comparable but not if the basis for the competitor's calculations is 16ºC, because at that temperature Sierrablen 28:5:5 would last for 7 months.