pH
It is important to test the pH of your soil to ensure the acidity levels are correct for the plants you are growing. Soil pH can differ from one area of your garden to another so it is important to test the soil pH where you intend to grow your plants. 

N - Nitrogen
Nitrogen is essential for vegetative growth - so it's important for leafy plants and grass. The correct amounts allow healthy growth - too much and the plant structure will be damaged.

P - Phosphorus
Phosphorus is an important nutrient required by plants for healthy root growth - making it very important for root vegetables. Phosphorous helps in the formation of buds and healthy stems. A lack of phosphorous will stunt plant growth.

K - Potassium/Potash
Potassium is important for the development of flowers and shrubs. The correct levels of potassium ensure flowers become more fragrant and have improved colour. In vegetable crops potassium helps to produce a netter quality crop and helps to make plants more resistant to disease.

to see how to use this Soil Testing Kit