It All Starts with Soil

By David Rodriguez

If your lawn, vegetable garden or any part of the landscape did not met acceptable expectations this past year consider, for a few well-spent dollars, a soil test. It all starts with your soil, and a good soil is one of the major key ingredients in growing predictable quality plants.

Ask yourself these vital questions: Do I have good soil? Does the soil smell good, taste good or even look good? What? In truth, this is NOT the most scientifically recommended approach on identifying the availability of the main nutrients, such as nitrogen, phosphates or potassium.

A soil test will help you come to an unbiased decision on purchasing the correct amounts of soil amendments, additives, supplements, and fertilizers. Bypass all the guess work and confusion. Pick a soil test that meets your specific needs.

It is crucial to know and understand how much nitrogen, phosphorus, potassium, and other major, or minor, essential nutrients are in the soil, as well as the pH (acidity or alkalinity). For example, most plants such as vegetables do not abundantly produce in improperly fertilized soils; therefore, visible signs of misshaped and/or small size fruit, leaf, or blossom shape and color-all are in line with lack of necessary soil nutrient levels.

The report (Routine Analysis) generated from the soil test provides you with the levels of nitrogen, phosphorus, potassium, calcium, and magnesium available to your plants before or after they have been planted. It also indicates the pH of the soil. Overall, these are the minimum criteria to properly prepare and fertilize your soil and insure that great harvest this season. If your plants have shown micro-nutrient symptoms, a micro test can also be provided.

Taking a soil sample is very easy. Just make sure your equipment is clean to avoid contamination of your soil sample. Here are four steps in collecting your soil sample.

Step 1 – Make a hole about 6-12 inches deep at the tillage zone with a spade or shovel.

(The tillage zone, typically 6 to 8 inches deep, usually contains a relatively uniform, high concentration of nonmobile nutrients. Below the tillage zone, the concentration is usually lower. Therefore a sample from the tillage zone will usually have a higher content of non-mobile nutrients which will lead to more accurate results.)

Step 2 – Take a slice of soil ½ inch thick and 6 to 12 inches deep, and keep it on the shovel. Use a knife and cut a strip, ½ inch wide away from the top. Then cut a strip, ½ inch wide away from the bottom. Place the center of the slice in a plastic bucket. (The usage of a plastic container is more desirable then metal, due to the possibility of potential ion exchange. Thus, the sample should not get contaminated or give fluctuating readings.)

Step 3 – Repeat these procedures 5 to 10 different areas throughout the intended growing area.

Step 4 – Mix all of the soil samples together, air dry on butcher paper or newspaper. Fill the soil sample bag to the line indicated on the side of the bag, and mail to:

Soil, Water, and Forage Testing Laboratory
2474 TAMU
College Station, TX 77843-2474

The Testing Laboratory provides nine unique, but specific soil tests. A basic routine analysis is the most common and costs about $10.00 per sample analyzed. Prices vary with the degree and necessity of details one desires.

For more information, contact the Master Gardener ‘Hotline’ or my secretary, Angel Torres at (210) 467-6575. Ask for a “Soil Test” kit. This includes the information, instructions, price list, and envelope for containing your sample. Visit the Texas A&M-Soil, Water and Forage Testing Laboratory at this link:

Results will be mailed to you normally in 2-3 weeks. Do not wait for spring! Late winter is (i.e. “right now”) the ideal time to start planning and properly preparing for your spring vegetable garden, lawn or landscape. An unbiased and accurate soil test will be the first step for success with any plant.

David Rodriguez is County Extension Agent-Horticulture, Bexar County. For more information, call the Master Gardener ‘Hotline’ at (210) 467-6575 or visit our County Extension website at, click under Horticulture and Gardening.

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