You’ll appreciate the convenience of the color-coded capsule system that reads the nutrients of your soil in minutes. By testing the nitrogen, phosphorous, potash and the ph levels (acidity and alkalinity) of your soil, you can determine whether to fertilize or adjust the ph levels for your plants growing needs. Take a sample of soil and mix it with water, transfer the solution into the desired holder, add the powder from the capsule, shake and watch the test results in minutes. The kit includes 4 test holders, 40 test capsules, 10 each for ph, n, p and k, instructions for adjusting the ph and fertilization guidelines and a listing of ph preference for over 450 plants.