A good soil test is essential because it lets you know the specific nutrient needs of your garden so you do not waste money on the wrong fertilizers. The soil test will also let you know whether you need to raise or lower the pH of your soil. Careful soil testing and correction of the soil to the specific needs of your garden assures that each crop gets exactly what it needs to grow and yield to its fullest potential. Here is why it is necessary that you know the soil pH, the nitrogen, phosphorus and potash content in your soil. Excessive nitrogen causes too rapid growth that results in softness of tissue and general plant weakness.
Plants suffering from nitrogen deficiency are more susceptible to disease, infection, and injury.
Excessive potash reduces a plant's resistance to droughts and frost injury and delays plant maturity. Since test results are sensitive to external factors such as ashes, never smoke while gathering or testing your soil and avoid touching the sample with your hands. Put samples in clean containers and label according to which part of the garden they were gathered from. It is best to take samples from each corner and the center of the plot in any case. The soil should not be too wet.