How to Test Nutrients in Soil

Alkaline vs. Acidic. Nitrogen. Phosphorus. Potassiaum. Like all living things, plants need nutrients to thrive. Many plants thrive in whatever soil they are planted in, but some plants, like gardenias, are temperamental and will not do well without an acidic soil. There are things you can do to adjust the nutrients in your soil, but first you must know what the soil in your garden contains. Testing your soil for nutrients is not difficult to do.

Things You'll Need

• Soil testing kit
• Shovel, trowel or bulb digger
• Plastic bag
• Permanent ink marker
• A piece of paper
• Paper cup
• Measuring spoon
• Plastic spoon
• Timer

Instructions

1. Use a shovel, trowel or bulb digger to gather one soil sample measuring 3 feet by 3 feet. Dig six to eight inches deep for the sample. If you are testing soil in a larger area, then more than one soil sample is needed. If the lot is larger than 10 feet by 10 feet, then soil samples can be collected further apart. than 3 feet by 3 feet. Mix multiple samples together in a plastic bag. Label the bag if you are doing more than one test.

2. Lay a piece of paper open on a place where it can be undisturbed overnight. Spread the soil sample on the paper. Remove any leaves, sticks or stones. Use the back of a plastic spoon and crush any lumps of soil that are larger than a pea. Let the soil dry, preferably overnight.

3. Follow the instructions in the kit for the particular chemical you’re testing for. For pH, you will fill the test tub with distilled water and drop the test tablet that tests for pH and add one cap of soil. Put the lid back on the tube and mix the soil and chemicals in the water by inverting the test tubes.

4. Prepare the test tubes for nitrogen, phosphorous and potassium by pouring distilled water in a paper cup. Then add the proper test tablets and mix with spoon. Pour the chemical water into the test tube and add the test tablet for the particular nutrient. Put the lid back on the tube and mix the soil and chemicals in the water by shaking or inverting the test tubes, until the soil disintegrates.

5. Allow the soil to settle before reading the results; one minute for pH and five minutes for nitrogen and phosphorus. For potassium, the results can be read as soon as the test tablet disintegrates.

6. Hold the test tube up next to the color chart in the soil testing kit to test for pH. The water will be red if the pH is 4.0, orange for 5.0, yellow for 6.0, light green for 7.0, dark green for 8.0 and purple for 9.0.

7. Hold the test tube up next to the color chart in the soil testing kit to test for nitrogen. Light orange is low, medium orange is medium and dark orange is high. Hold the test tube up next to the color chart in the soil testing kit to test for phosphorus. Light blue is low, medium blue is medium and slate gray/blue is high. Hold the test tube up next to the color chart in the soil testing kit to test for potassium. Dark gray is low, medium gray is medium and light gray is high.

8. Pour the reacted test water down the drain with lots of running water. Dispose of treated soil samples in the trash.

Tips & Warnings

• Test tablets contain chemicals. Do not ingest. Keep out of reach of children.