It's vital to know the existing pH, Nitrogen (N), Phosphorous (P), and Potash (K) levels in garden soil. The rapitest Soil Test Kit remains the standard for home soil testing. The kit includes all components needed for (40) tests: (10) each for pH, Nitrogen, Phosphorus, and Potash. The patented color comparator system allows for easy color comparisons versus a typical printed color chart. Extensive yet simple instructions and recommendations for over 400 plants are included. Test results will enable the gardener the amend and fertilize appropriately, ensuring the best possible results