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Notes regarding fertilisers and their uses
SOME NOTES THAT MAY BE HELPFUL IN SELECTING FERTILISERS, ETC
Manures and composts are excellent soil conditioners but are relatively low in nutrients.
Plants take 3 major elements from the soil for growth:
- nitrogen (N) for leaves
- phosphorus (P), for roots, and
- potassium (K), for fruit and flowers
The following charts indicates the approximate percentage of these elements in the various fertilisers.
Organic |
%N | %P | %K |
| Animal manure | 0.6 | 0.1 | 0.5 |
| Garden compost | 0.5 | 0.3 | 0.8 |
| Bone meal | 3.5 | 20 | - |
| Dried blood | 21 | - | - |
| Fish, blood and bone | 6 | 6 | 6 |
| Hoof and horn | 13 | - | - |
| Rock potash | 5 | 8 | 10 |
| Rock phosphate | - | 26 | 12 |
| Wood ash | 0.1 | 0.3 | 1 |
Inorganic |
%N | %P | %K |
| Growmore | 7 | 7 | 7 |
| Potassium sulphate | - | - | 49 |
| Potato fertiliser | 12 | 11 | 18 |
| Rose food | 5 | 7 | 10 |
| Sulphate of ammonia | 21 | - | - |
| Sulphate of potash | - | - | 48 |
| Superphosphate | - | 16 | 17 |
| Tomato fertiliser | 5 | 4 | 11 |
| Vitax Q4 | 5.3 | 7.5 | 10 |