Types of fertilisers and when they should be used

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Types of fertilisers and when they should be used

So, you need to find out more about fertilisers, right?

All fertilisers are chemical by nature and can be either organic or inorganic. The difference between the two types of fertilisers is their carbon content. Organic fertilisers contain carbon while inorganic fertilisers have no carbon. Examples of organic fertilisers are manures made from animal excrement and 'blood and bone' made from waste products from abattoirs. Fertilisers can come in powdered, granular or liquid forms.

Have a look at the following different types of fertiliser formulations available on the market and see if you recognise their features and if you can think of an actual product that is used in horticulture:

Types	Features
granules	irregular shape and size
pelletised	round even sized particles
prills	round even sized particles coated with a biodegradable plastic
pellets	short cylindrical extrusions
liquids	solution or emulsion

Always read the package on fertilisers to see what ingredients they contain and to see what planted areas they should be used for. For example 'Blood and Bone' is an organic fertiliser made from animal waste products, is slow releasing, primarily designed for long-term feeding, does not contain potassium and is especially good for building up poor sandy soils.

It's important to remember that fertilisers are:

expensive to use and should be used wisely, and in the right quantity
harmful to the environment and need to be used carefully.

When should I use fertilisers?

Slow-release fertilisers can provide nutrients for a new plant over its first few months in a new site. This means that the plant has enough nutrients to ensure steady growth.

Slow release fertilizers can come in the form of large tablets or in the form of small prills (such as Osmocote® or Nutricote®). There are also organic fertilizers such as well-rotted manure, blood and bone and seaweed-based liquid fertilizers. Your employer may prefer you to use these.

You need to be careful of one thing, though. Not all fertilisers suit all types of plants. Make sure you use the correct fertiliser and the correct amount of fertiliser for the plant you are planting. Using the wrong fertiliser can poison a plant and even kill it!