Soil Identification

Soil Identification

Parker County may be known for its peaches and crape myrtles, but it’s not because of our fabulous soil. This County has some of the most frustrating and unusual soil combinations in the entire State. Because of this, it is important to assess your soil before you select plants for the landscape.

 What are the characteristics of your soil?

• What is the pH?
• Is it clay, sandy, caliche?
• What is the nutritive content?
• Are the soil characteristics consistent throughout the property?

All of these factors will impact the success of the plants you select for your landscape, so don’t neglect this important step. There are varying types of soils in Parker County and knowing what kind of soil you have and what nutrients it contains is a necessary step.

Parker County Soils
Geographically, Parker County is located in the Western Cross Timbers land resource area. We have an area of 905 square miles with a variety of soils. Some areas are sandy, some are clay, some are shallow and rocky, and others are pure caliche. Caliche is calcium carbonate that binds with gravel, sand, clay and silt to form a particularly difficult soil in which to garden. There are very few areas in the County that are considered fertile. As a result, amending the soil is a necessity for gardeners. Our soil is predominantly alkaline (higher pH), and the average rainfall is 33 inches per year.

If you compare this region to the southern United States from Georgia to East Texas, where the gardens featured on TV and in popular magazines are located, you will see that Parker County has less rain, less organic matter in the soil, and an alkaline environment rather than acidic. This means that many acid loving plants like azaleas, dogwood, camellias, gardenias, and pine trees will not do well here even though those plants thrive about 90 miles to the east. It also means that water loving plants are going to require significant assistance from the public water supply. Most residents in North Central Texas have come to appreciate a unique variety of native and adaptive plants that thrive in our particular environment. If you want a happy, healthy landscape, it may be necessary to become familiar with these plants.

Soil pH
The term pH is the measure of acidity or alkalinity of soil. Soils that are neutral have a pH of 7. Soils that are acidic have a lower pH while those that are alkaline higher. Soils that are near neutral, or slightly acidic (pH of 6 to 7), are ideal for most plants. Parker County soils are generally neutral to alkaline, with a pH of 7 to 8.5.

A soil test is a great way to determine the pH, nitrogen, potassium, phosphorus, and micronutrient content of your soil. This can be done at the Soil, Water & Forage Testing Lab at Texas A&M University. Sample bags and instructions are available at the County Extension Office. From your sample area, take several litter free soil samples from 6 inches deep if possible. Mix the various samples in a clean plastic container and fill the pint sample bag with the composite soil sample. Complete the information form as fully as possible, and ship it to the lab along with the fee. You will receive a report of the soil analysis in a very short time. If you have several areas of interest that may have varied compositions, take soil samples from each individually.

Soil Characteristics
The physical characteristics of soils in Parker County vary widely. Many of these soils will need to be amended to achieve good plant growth.

Clay soil is very tightly packed with tiny pore spaces. Working fully composted organic material into clay soil will help loosen it up, provide larger air spaces, and improve water movement. Expanded shale is a product that will produce the same results without adding nutritive value. The tiny shale pellets increase moisture and air content and loosen the soil. They do not degrade over time and require only one application. It is recommended to work 3 inches of compost and 3 inches of expanded shale into a new bed with sticky clay soil.

Sandy soil is well-drained soil with larger pore spaces and fewer nutrients. Working fully composted organic material in to sandy soil will help it to retain moisture and improve the nutrient value.

Rocky soil tends to be shallow, and often the only viable method is to build raised beds and introduce soil. Drainage is often a problem in rocky soil, requiring planning and intervention.

Once you know the physical characteristics of your soil, you can plan accordingly and add the appropriate amendments. Combine this information with the detailed results of a soil test, and you know exactly how to fertilize your landscape.

Soil Nutrients
Plants require nitrogen (N), phosphorus (P), and potassium (K) more than any other essential elements for growth. With your soil sample results, you have an idea of the quantity of these elements contained in your soil. If you have deficiencies, the soil can be amended. Generally for Parker County, the greatest need is for more nitrogen and less phosphorus and potassium.