This soil kit is extremely easy to use and includes everything you need to measure the 4 main parameters necessary for strong plant growth. Nitrogen, Phosphorous, Potassium and pH can all be measured with this kit, simply take a sample of the soil, dilute in water and then add the supplied chemical reagent. The result is a coloured solution which is compared to the chart provided to determine the concentration of the element tested.The concentration is given in an easily-understood trace, low, medium and high range scale and the HI-3896 is supplied with an extraction solution which facilitates precipitation of suspended solids so that measurement can be taken immediately. Everything is included for 25 tests of each of the 4 parameters to be made. Ideal for the busy professional gardener, or garden centre.