About Soil Testing

The soil test is an excellent measure of soil fertility. It is a very inexpensive way of maintaining good plant health and maximum crop productivity.

The standard soil test provides the status of phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), pH, cation exchange capacity, lime requirement index, and base saturation. Additional tests are also available for iron (Fe), zinc (Zn), manganese (Mn), soluble salts, and nitrates.

This information courtesy of Lowes Garden Center

Why Test Soil?

For a better lawn or garden, start with a soil test. Testing your soil allows you to:

  1. Select the right plants for your garden—A pH test, for example, determines how acid/alkaline your soil is. You can then pick plants that will survive and thrive in your soil conditions.
  2. Remedy your soil problems by determining what key elements are missing from your soil.
  3. Monitor nutrients—Nitrogen, phosphorous and potassium are all needed for plant growth, color and blooming.

Soil test kits are available at commercial garden centers. These kits allow you to get an immediate analysis of your soil's pH. Your local agricultural extension office will also test your soil sample for pH and nutrient levels (usually for a small fee). Most offices provide you with a sterile container for your sample and a form to answer questions about your garden, where you live and the plants you wish to grow. The soil analysis usually takes a few weeks to get back to you. The analysis includes detailed results and suggested amendments specific to your region.

How to Test Soil

You will need:

  • Clean bucket
  • Garden trowel
  • Clean container
  • Newspaper

Steps:

  1. Thoroughly clean the tools you are using to collect the soil sample.
  2. In the planting area, dig five holes 6-8" deep.
  3. Take a 1/2" slice along the side of a hole and place it in the bucket. Repeat this process for all holes.
  4. Collect samples from different areas that will be growing similar plants.
  5. Mix the soil in the bucket. Spread the soil on a newspaper to dry out. Collect a pint for your sample.

Helpful Hints:

The best time to test your soil is in the late fall or early spring. This gives you the time to make adjustments before you plant your garden, since soil corrections may take a few months to become effective.

Wet soil can give a false test reading. Be sure to take the sample when the soil is fairly dry. You may want to check your soil more than once to verify your results.

What do the results mean?

Result Correction
High pH Soils with a high pH are alkaline. To lower pH, add sulfur into the soil surrounding the existing plants or into new planting beds.
Low pH A low pH reading is an indication that your soil is too acidic. To correct the problem, add lime to the soil and mix well.
Low nitrogen This is a common problem with soil. Use synthetic or natural, nitrogen-rich fertilizers according to the rate suggested by the manufacturer.
High nitrogen High nitrogen levels are usually the result of soils that have been over-fertilized. Water the soil well and stop adding fertilizer for several months.
Low phosphorus Mix superphosphate or bone meal into your garden soil, making sure to mix these amendments into the soil thoroughly.
High phosphorous This problem is usually caused by too much high-phosphate fertilizer. Do not use phosphorous-rich fertilizer for two years, and grow an abundance of plants to use up the excess.
Low potassium Work in potash or wood ashes. Avoid using wood ashes around acid-loving plants because these are alkaline and may diminish the growth of the plants.
High potassium Add nitrogen and phosphorous to help balance the soil, but do not add potassium-rich fertilizers or soil amendments for two to three years.
Poor drainage Heavy clay soil tends to drain poorly. Thoroughly mix in peat moss, compost or other organic materials to help loosen the soil.
Too much drainage Sandy soil drains too quickly to hold necessary nutrients. Add organic materials to remedy soil that drains too quickly, just as you would for poor drainage conditions.

Improving your soil's pH

After you have received the results of your soil test, it is time to make improvements. The figures below equal pounds of limestone needed per 1000 sq. ft.

  Sand Loam Clay
Present pH To 6.0 To 6.5 To 6.0 To 6.5 To 6.0 To 6.5
4.8 60 85 100 140 140 200
4.9 55 80 95 130 125 185
5.0 50 75 85 28 115 160
5.1 45 70 80 115 100 150
5.2 40 65 70 110 90 135
5.3 35 60 65 100 75 125
5.4 30 55 55 95 65 110
5.5 25 50 50 85 55 100
5.6 20 45 40 80 45 90
5.7 15 40 30 70 35 80
5.8 10 35 20 65 25 70
5.9 5 30 10 55 15 60
6.0 — 25 — 50 — 50
6.1 — 20 — 40 — 40
6.2 — 15 — 35 — 30
6.3 — 10 — 25 — 20
6.4 — 5 — 15 — —

Improving Soil for New Soil Beds

You will need:

  • Rotary tiller
  • Shovel
  • Soil amendments or additives (as determined by your soil test results)
  • Garden rake

Then follow these steps:

  1. Water the garden area well a few days before tilling the soil.
  2. Run the tiller in rows as if you were mowing. If the first pass was very difficult, make another along the same path.
  3. Spread amendments over the tilled soil. If adding several amendments, put one on top of the other in even layers.
  4. Using the rotary tiller, blend the amendments into the soil to a depth of 6 - 8."
  5. Rake the surface level and then water it well to settle the soil.

Improving Soil for Existing Beds

You will need:

  1. Amendments (as determined by your soil test results)
  2. Garden fork
  3. Steel rake

Then follow these steps:

  1. Break up the soil about 2 - 3" deep around plants with the garden fork.
  2. Sprinkle the amendments and blend them evenly using the garden fork.
  3. Level the area by raking in one direction and then the opposite. Water well to soak.
AccugrowT Soil Test Kit

AccugrowT Soil Test Kit

You can easily perform a soil test whenever the need arises.
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