How to Use a Soil Test Kit to Test for Nutrients

One of the more important tasks on my Spring Home Improvement list is testing the garden soil for nutrient content. Using inexpensive test kits from a local garden center, I test the soil in each raised bed in my garden. The tests indicate the levels of nitrogen(N), phosphorous(P) and potash/potassium(K) in each bed. The results help me determine which nutrients are depleted and which are plentiful so I add the correct balance of fertilizer to each bed, resulting in a healthy and bountiful garden.

How to Test Your Soil Using a Kit
1. Select a soil test kit that provides a comprehensive chart system. The kit I use has four small tubes; each has a colored cap and a matching colored capsule. The kit includes tests for pH balance, nitrogen, phosphorous and potash. Other available kits provide litmus strips. Either method requires matching the resulting color, either of liquid in tubes or on litmus strips to a colored chart.

2. Keep the soil moist for several days before performing the tests. On testing day, turn the soil in a small section of each bed or in several areas around the garden. Use soil from 4 to 5 inches below the top soil for accurate results.

3. Follow the manufacturer's instructions to obtain samples. My kit calls for placing 1 part soil to 5 parts water into a small jar and shaking vigorously. I used a clean canning jar with a lid and filled it approximately 1/5 of the way with soil and then added water to fill the jar.

4. Allow the sample to sit in daylight for several minutes until the sediment settles at the bottom of the jar. My kit then called for adding a small amount of the sample to each tube and emptying the corresponding colored capsule into the tube. For example, the purple capped tube is for testing for nitrogen, so I emptied the purple capsule into that tube. I then shook each tube vigorously.

5. Check the results against the color chart provided in the kit. The results may take approximately 10 minutes to show, and are expressed in general terms. For example, the pale pink color in the purple capped tube indicates that the nitrogen level in the test bed is "Very Low," but the phosphorous level is "Very High."

6. Perform a soil test for each bed or area in the garden and note the results in a notebook.

How to Add the Right Nutrients to Your Soil
1. Use the results to determine the right mix of fertilizers for each area or bed in the garden. For example, the results of the first bed tested in my garden indicates a deficiency in nitrogen, but phosphorous and potash are plentiful.

2. Note that packaged fertilizers indicate content with numbers that correspond with the macronutrients nitrogen(N), phosphorous(P) and potash or potassium(K). A package label may read, "8-5-5", meaning 8 parts N, 5 parts P and 5 parts K.

3. Select a fertilizer with the number corresponding to the nutrient that is deficient in the bed or area. For example, to add nitrogen, the above mix may be suitable, though a higher number for nitrogen may be desirable.

4. Turn the selected fertilizers into the areas or beds, mixing them into the soils and then smoothing the soil surface with a rake.

5. Wait a few days before planting your spring crops. Fresh fertilizer may burn young, tender seedlings or inhibit seeds from germinating.

Tip
Check the pH of your soil as well. Vegetables prefer soil with a pH balance of between 6 and 6.9 for optimal growth.