Controlled Release Fertilizers

Controlled release fertilizers (CRF) include a special coating technology that helps releasing small amounts of nutrients (nitrogen, phosphate, potassium, and trace elements) over a longer period, matching the plant’s nutritional needs during its growth cycle.

Over 50 years ago, the first CRF ICL’s Osmocote® changed the industry, marking the start of a whole new principle of fertilizer application. Today, CRFs are used all over the world in ornamental horticulture.

Osmocote’s CRF technology is used in several ICL’s leading brands, the latest being Osmocote 5. For a long time, nursery stock growers have been relying on products from the Osmocote Exact Standard range, featuring different longevities and analyses for specific crop conditions.

	An organic resin coating covers each granule and acts as a sort of membrane that regulates the daily release of nutrients to the plant.
	Each granule contains NPK, B, Cu, Fe, Mn, Mo and Zn.
	Water penetrates the coating and dissolves the nutrients inside the granule.
	Nutrient release starts as soon as a part of the nutrients has dissolved.
	Osmotic pressure releases the dissolved nutrients through the granule coating.
	When all nutrients have been released, the resin coating breaks down gradually.

Watch our video to learn more about the Osmocote controlled release fertilizer working principles.

• Highest nutrient use efficiency

CRFs are considered the fertilizer technology with the highest nutrient use efficiency thanks to the consistent controlled release of nutrients over time. In comparison, conventional fertilizers dissolve in the soil immediately after application, only providing nutrition for a short period of time. Multiple fertilizer applications are necessary to ensure that the plant gets the nutrition it needs.

• CRF: a sustainable choice

CRFs are an enhanced fertilizer technology that contributes to a more sustainable, environmentally friendly way of fertilization. The consistent, controlled release of small amounts of nutrients over a longer period:

– lowers fertilizer input and applications
– improves plant health, resilience, and color
– minimizes leaching to the environment

• Matching the plant’s needs

Salinity, soil pH and microbe activity, water quality and rain do not influence the release of nutrients of a CRF. Only temperature affects the nutrient release and therefore also the longevity of the CRF. Granules work in temperatures above freezing, with the membrane regulating the daily release of nutrients. The pre-defined product longevities are applicable at an average daily temperature of 21 degrees Celsius. Higher temperatures speed up the nutrient release and thus shorten the longevity. Lower temperatures slow down the release of nutrients, thus extending the longevity. This way, CRFs can match the plant’s need perfectly during its life cycle.