| Fertilizers are grouped according to their mode of | | | | suggests, balanced fertilizers, also known as complete |
| manufacture or origin. Organic fertilizers are derived | | | | fertilizers, contain an equal proportion of each macro |
| from naturally occurring organic materials, such as | | | | nutrient being typical. Specific fertilizers, on the other |
| animals and plants. Some of the most widely used | | | | hand, have different ratios. They are usually sold |
| are bone meal, high in phosphorus, fishmeal, fish, | | | | labeled as beneficial for particular plants, such as |
| blood and bone, hoof and horn, high in nitrogen and | | | | lawns or roses. Straight or simple fertilizers are the |
| seaweed meal, also high in nitrogen. They are slow | | | | final group and these supply just one of the macro |
| acting because they have to be broken down by | | | | nutrients, such as super phosphate or potassium. To |
| micro organisms in the soil before the nutrients they | | | | make selection even more complicated, some |
| contain become available to plants. The rate of | | | | fertilizers are supplied in combination with other |
| breakdown of the fertilizers varies according to the | | | | chemicals, such as a fungicide, insecticide or herbicide. |
| prevailing conditions, if it is warm and moist | | | | They are a convenient but usually an expensive way |
| breakdown speeds up, then it is cold or dry it slows | | | | of buying fertilizer. Slow release fertilizers are |
| down. | | | | inorganic fertilizers that have been coated in a special |
| Nutrients are thus released when plants need them | | | | resin so that the nutrients are released slowly over |
| most and are growing strongly. For these reasons | | | | time. They mimic organic fertilizers in that they |
| organic fertilizers are acceptable to most organic | | | | release more nutrients when the soil is warm and |
| growers. Inorganic fertilizers are man made. Most are | | | | moist, just when the plants need it. You can buy |
| manufactured, but a few, such as rock potash, are | | | | slow release fertilizers that will last from a few |
| naturally occurring minerals that are mined. They are | | | | weeks to the whole season. Because they cannot be |
| concentrated and usually quick acting because they | | | | washed away they are particularly suited for use in |
| are soluble in water so are immediately available to | | | | containers that are regularly watered throughout the |
| the plants. Although effects can be immediate, such | | | | growing season. Fertilizers are also available in liquid |
| fertilizers are easily leached from the soil by heavy | | | | formulations. Liquid grow more or liquid seaweed |
| rains, especially in winter and on well drained soil. | | | | extract will promote general plant growth, but a high |
| These fertilizers can be further grouped according to | | | | potash feed, such as rose or tomato fertilizer, will |
| the amount of N, P and K they contain. As the name | | | | encourage flowers and the formation of fruit. |