Luster Leaf Rapitest Soil Kit Test for pH-N-P-K

Takes the guess work out of determining whether your soil pH needs adjusting or if nitrogen, phosphorus and potash should be added in the form of fertilizers. Just mix soil and water together, pour off solution into comparator, add one tablet, shake and compare to color chart. It's just that easy. Contains supplies for 40 tests - ten each for pH, nitrogen, phosphorus and potash.