pH is a numeric expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid, and higher values more alkaline. The pH is equal to -log10 c, where c is the hydrogen ion concentration in moles per liter.
Why Test for pH?
If you have a swimming pool, you are familiar with the importance of maintaining a certain pH value. Avid gardeners are also familiar with the importance of knowing the pH of their soil as certain plants grow better in acidic soils and other plants grow better in alkaline soils. For example, blueberries want their soil pH levels between 4.0 and 6.0 while mint thrives at 7.0 to 8.0. When pH levels are out of balance for the plant requirements, the gardener adds needed amendments to the soil.
Avid gardeners test the soil periodically throughout the growing season but it is especially recommended to test before planting in the spring and when preparing beds in fall to ensure that you are creating a healthy place for your edibles and other plants to grow.
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Loving Garland Green is testing soil tonight and celebrating the beginning of spring! Come join us at 6:30pm tonight. Bring a soil sample if you like.
Tonight is Loving Garland Green’s third Monday of the month meeting. (You are welcome to come—6:30 to 7:30PM -216 East Kingsbridge 75040.) On the third Mondays we have member presentations and other activities. Tonight we will be testing the soil in our gardens and from the Garland Community Garden using the rule of thumb method described below and using a soil testing kit that was purchased at a big box garden store for $12.
I am testing: 1) some compost from the Mesquite landfill 2) Two different commercial garden soils 3) some soil from my garden and 4) some soil from a bed at the Garland Community Garden where I plan to plant green beans.
We will also be packaging some green bean seeds that we plan to give away at an upcoming Garland Community event to be held on Sunday afternoon from 2 to 4 PM—but that’s another story I’ll tell later in the week.
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THREE LEVELS OF SOIL TESTS: From "Rule of Thumb" to Professional
1. THE ALMOST FREE RULE OF THUMB SOIL TEST – only a rule of thumb for pH.
You can test your garden soil pH with vinegar and baking soda. Collect 1 cup of soil from different parts of your garden and put 2 spoonfuls into separate containers. Add 1/2 cup of vinegar to the soil. If it fizzes, you have alkaline soil, with a pH between 7 and 8. Add distilled water to the other container until 2 teaspoons of soil are muddy. Add 1/2-cup baking soda. If it fizzes it is acidic. [The soil in the Garland area, which is part of the Blackland Prairie ecoregion as is most of Dallas County, is primarily alkaline with pH variance from 7 to 8.]
2. THE INEXPENSIVE COMMERCIAL SOIL TEST KIT- more accurate test for pH and also test for Nitrogen (N), Phosphorus (P) and Potassium (K).
You can purchase a soil test kit from a local nursery or from a big box garden store. They cost about $12 and can test not only the pH but also the Nitrogen, Phosphorus and Potassium (NPK) levels of your soil. NPK ply a vital role in plant growth just as vitamins, minerals, carbohydrates and protein play important roles for our health.
3. THE PROFESSIONAL SOIL TEST—the most reliable
You can obtain soil testing bags and instructions from the Dallas County Extension office and send the samples off to Texas A&M for testing.
Several different soil tests are available at the Extension Soil, Water, and Forage Testing Laboratory. These include tests for routine nutrients, micronutrients, boron, detailed salinity, lime requirement, texture and organic matter. After taking the soil sample, select the appropriate test to obtain the desired information.
The routine test determines the soil pH, salinity, nitrates (NO3-N), and levels of the primary nutrients (P - phosphorus, K - potassium, Ca - calcium, Mg - magnesium, Na - sodium, and S - sulfur) available to plants. The routine test will provide the basic N-P-K fertilizer recommendation for selected crops. This test meets most application needs.
For more information on this opportunity, download this document:
http://soiltesting.tamu.edu/publications/E-534.pdf