How to Determine the Nitrogen in Soil Samples

Collect the soil sample by digging down 2 to 3 inches in the ground with a spoon or hand trowel. Insert the sample into a clean plastic sandwich bag or a plastic cup.

Open the soil test package and locate the vile for the nitrogen test, which is typically purple. Read the package instructions or look at the vial to determine how much of the soil sample to add. Insert the sample into the vial. Typically, you only use 1 to 2 teaspoons of soil for each test.

Locate the waterline on the vial and add distilled water to the vial until reaching the line. Use only distilled or purified water, since tap water contains minerals that impact the test results.

Locate the small capsule that tests for nitrogen and is typically purple, which corresponds to the color of the vial. Open the capsule gently and pour the contents into the vial.

Close up the vial and shake it vigorously for 10 to 15 seconds. Set the vial on the counter and wait at least 10 minutes. Refer to the package instructions for the amount of time for your specific testing product.

Examine the vial and compare the color of the water to the chart provided to determine the level of nitrogen in the soil. The chart will indicate whether the nitrogen levels are high, low or in between.