pH, nitrogen, phosphorous and potassium are the key elements in soil that establish the health of your plants. Soil pH is important because it affects the availability of nutrients to plants and the activity of microorganisms in the soil. Plant nutrients, including nitrogen (N), phosphorous (P) and potassium (K) are most readily available at a pH range of approximately 6 to 7. Analyze your soil quickly with these easy to use pH and soil test kits to determine how to optimize growth.