Luster Leaf's 1601 Rapitest Soil Test Kit is an innovative and inexpensive way to test a number of soil conditions using an easy capsule system and unique color comparators. The kit contains 40 tests including 10 for each pH, nitrogen, phosphorus and potassium levels. Simple, fast and accurate, no experience is required to perform the tests. Simply mix soil with water then pour the water off, dissolve a test capsule and compare the color to the included chart. The chart includes pH and NPK levels for more than 100 plants, complete instructions are also included for adjusting soil conditions and fertilization.