An Introduction To N:P:K
During the growing season plants absorb important nutrients and minerals from the soil, these need to be replaced if your plot is to maintain a high level of productivity and yield. Most general-purpose fertilisers have an N:P:K rating which relates to the three primary elements needed for healthy plant growth, the higher the rating the more of that element exists within the fertiliser.
Nitrogen (N)-Supports the growth of the vegetative parts of plants, stems and leaves. It is vital for the production of chlorophyll, which allows plants to carry out photosynthesis. Leafy vegetables such as spinach, cabbage and lettuce have a high nitrogen requirement as does lawn grass. Lack of nitrogen causes poor, stunted growth with spindly stems and yellow or discoloured leaves. Nitrogen washes out of the soil so feeds need to be applied little and often, especially during the growing season.
Phosphorus (P)- Stimulates seed germination and root development, increases stem strength and improves fl ower formation. Root vegetables need plenty of Phosphorous to aid development. Lack of phosphorus causes poor, stunted growth. Plants produce little or no fl owers, have weak root systems or a bright green or purplish cast.
Potassium (K)- Essential for flower and fruit production and improves drought, pest and disease resistance. Often referred to as the “quality element,” because of its importance to many of the features associated with quality, such as size, shape, colour, and taste. Potatoes, fruit and tomatoes all need high levels of Potassium to crop well. Plants low in potassium are stunted in growth and provide lower yields. Excessive levels of potassium can lead to magnesium and calcium deficiencies. Minerals and trace elements are also an important requirement for good plant health. Over time, with each and every harvest, the soil is depleted of these vital
ingredients and they also need replacing.