Fertiliser Action

The speed of process of how nutrients are made available to a plant, of which three actions are often identified:
• Controlled release, which is by an artificial fertiliser often with a coating which dissolves or degrades and gradually (and in theory, relatively uniformly) releases nutrients over an extended period of time, for example 3-months or greater.
• Fast release is where the nutrient. Becomes readily available to a plant, typically within 7-10 days following application. These fertilisers are usually, inorganic in origin, with an example being ammonium sulphate. Care does need to be taken with fast release fertilisers as there can be an undesirable flush of growth, especially during naturally higher growth periods, so application rates need to be appropriate for the time of year, often being less than might be suggested on a fertiliser bag.
• Slow release takes longer to break down and be made available for plant uptake, often (but not always) being organic in origin, and is typically used to distinguish between manufactured controlled release fertilisers and slower release non-manufactured products.