Oregon Agriculture in the Classroom Logo
Lesson Overview
  • 100 Minutes
  • 1, 2, 4, 5
  • 6th - 12th Grade
  • State Standards:
    NGSS: MS-LS1-5, MS-LS2-5, MS-LS1-4, HS-LS2-4, HS-ESS3-2 CCSS: WHST.6-8.1, WHST.6-8.2, SL.8.1, Math: 6.RP.3, 7.RP.3,

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Materials List

Soil Testing Kit* (per student group)
•One nitrogen, phosphorus and potassium comparator with capsules.*
•One pipette*
•Paper cups*
•Spoon or shovel*
•Activity Page: Testing Soil Nutrients (N-P-K)*
•Masking Tape
•Paper Towel
•Liquid Measuring Cup
•Jar with lid
•Distilled Water
*Materials Available from Oregon Agriculture in the Classroom.

Testing Soil Nutrients (N-P-K)

Categories: Math , Kits , Science , Soils

Students will discover that plants need an adequate amount of nutrients to grow and stay healthy. Plants uptake nutrients from the soil, so it is important to test soil regularly to determine if there are enough nutrients to support plant growth. The soil test kit will help students identify whether soils in their garden, yard, park, etc. are fertile or deficient in nutrients. Keep in mind that all plants need nutrients, but requirements vary depending on the type of crop, shrub, tree, etc.

Part I: Preparing Soil Samples
1)Divide students into five groups. Have each group use a spoon or small shovel to gather soil samples in the paper cup. Ensure they avoid touching the soil with their hands, as this may alter test results.

Teacher Note: Encourage each group to get a sample from different areas in the garden or around trees and shrubs in order to have the best overall representation of soil nutrients.

2) Dump the soil out on a paper towel to allow soil to dry naturally if needed. Use this time to break up clumps and remove small stones before testing.

3) Place 1/4 cup of soil into a clean jar and add 1 1/4 cups of distilled water.

4) Place the lid on the jar and shake or stir the soil and water continuously for one minute.

5)Using a piece of masking tape, label the jar with the names of students in the group.

6)Set the mixture asside and allow it to stand until it settles. This usually takes 30 minutes to 24 hours depending on the type of soil.

7) Have students refer to the worksheet and hypothesize if each test will result in soil being depleted, deficient, adequate, sufficient or in surplus amounts for each nutrient.

For full instructions, please download our PDF