How to Test Soil
Many questions come up when one is gardening and trying to grow crops:
What fertilizer should I use? How much fertilizer should I use? Why aren’t my plants healthy?
This blog post will walk you through the steps of testing your soil to determine what nutrients are actually available for your plants.
Why Should I Test My Soil?
If a gardener is having trouble with yellowing of leaves, weak stems, or keeping plants alive as a whole, they will want to test their soil to see what the problem is. A soil test tells you the amounts of NPK: nitrogen, phosphorus, and potassium. Most soil tests will also show the level of pH and what should be done to lower or raise it.
Plants require a certain level of these nutrients and pH, and the only way to determine what your soil contains is to perform a test.
Nutrients
NPK — Nitrogen, phosphorus, and potassium — all play key roles in the development of a plant.
Nitrogen (N): the main component of chlorophyll, supports amino acids
Phosphorus (P): plays a main role in photosynthesis, storage of energy, and cell growth
Potassium (K): helps movement of water, nutrients, and carbohydrates in plant tissue, regulates photosynthesis, and exchanges oxygen and carbon dioxide.
pH: Plants will thrive in a pH level between 6.5–7.0 as this is where most minerals and nutrients thrive.
How to Test
Materials needed:
- soil testing kit
- soil sample
- distilled water
- jar
- Gather the sample. Ensure the soil is from around 5 inches below the surface.
- Create a soil-water mixture. Use the jar to make a 1 parts soil to 5 parts distilled water mixture. This will be used in each of the tests for N, P, and K.
- Test the pH. Fill the green-capped tube to the first line with soil. Pour the pH-labelled powder in the tube and add distilled water. Cap the tube and shake vigorously. Allow the soil to settle and compare the color of the water to the chart provided.
- Test for N, P, K. In most soil testing kits, the tubes are color-coded based on the nutrient they are used for. Purple is for nitrogen, blue is for phosphorus, and orange is for potassium. Use the dropper to fill the tube with water from the jarred mixture to the fourth line. Pour the appropriate powder into each tube. Shake well and allow 10 minutes to pass before determining the color.
- Compare the colors to the chart. Each nutrient will show a different color based on their level in the sample. A brighter, deeper color means the nutrient is rich. A lighter color means the nutrient is deficient.
The test is complete. Record the levels of each nutrient and purchase a fertilizer according to the levels found in the test. Research each type of fertilizer and determine which is best for your soil.
