Main fertilizers

Fertilizers are substances intended to supply plants with nutrients. Some organic amendments, including compost and composted manure, also act as fertilizers.

Plants need a variety of nutrients in order to grow and thrive. Some of these elements come from the air and water, but most are drawn from the soil, by the action of microorganisms. The gardener’s job is to feed the soil and the organisms in it, so that they can in turn feed the plants.

The best way to feed the soil is to add compost or composted manure to it on a regular basis. By using different kinds of compost and manure over the years, you can ensure that your plants have access to a full range of nutrients.

Fertilizers are used along with compost and composted manure, largely in the following circumstances:

• when soil test results show a mineral deficiency,
   
• to pep up a plant that has suffered considerable stress from disease, insect pests, drought, overpruning, transplanting, etc.,
   
• to increase plant yield and vigour;
   
• for growing plants requiring a lot of fertilizer,
   
• for growing plants in pots or containers.

There are two types of fertilizers: natural (organic or mineral) fertilizers and synthetic (chemical) ones.