Healthy Soil, Happy Plants

Healthy soil is essential for a successful garden! It’s disheartening to spend valuable time and money on plants that don’t thrive. But it’s often the quality of the soil, or lack thereof, that’s to blame for gardening woes.

Achieve healthy soil by addressing these basic necessities:

  • An adequate moisture level in the soil can be obtained.
  • The soil must be deep enough and of a texture that allows free movement of air and water.
  • Ensure the soil pH is within the acceptable range for the plants that will be grown in it.

Texas soils tend to retain water, which is good for dry summers, but can literally drown plants in spring or fall rains. Properly preparing the planting bed will allow the roots of your new plants to grow quickly. Deep water the soil and allow it to dry an inch or two down before you water again to further encourage deeper root growth in your new plantings.

The heavy, sticky clay soil in our region is deficient in air and organic matter. So, before you plant, the soil needs to be amended. Plant roots don’t get enough oxygen in unamended clay soils, but raised beds and other amendments help.

First, raised beds are recommended to improve drainage and growing conditions by lifting plant roots above poor soil. The height of raised beds also makes them easier to maintain. For vegetables, aim for 12 to 18 inches high. For all other ornamental plantings, 8 to 12-inch beds work great.

The best soil amendments for successful Texas garden beds are expanded shale, composted cotton burr, aged leaf mold compost, microbes, and fertilizers.

Expanded Shale

Expanded Shale is a gravel-size rock pumped full of air that aerates clay soil, making it easy to work and improving soil drainage. You only need to add expanded shale to the soil once and work it into the beds to a depth of 4 to 8 inches. Furthermore, plants have larger, healthier root systems when used with expanded shale.


Compost is made up of decomposed organic material produced when bacteria breaks down in soil. The nutrients in compost feed plants slowly, improve soil structure, and attract earthworms for soil aeration.  You can create your own compost at home or purchase ready-to-use options like aged leaf mold compost or composted cotton burr,  ideal for amending clay soils.

Health Soil

Healthy soil is full of microbes (bacteria, fungi, and other organisms). Microbes recycle nutrients found in dead plant and animal matter back into the soil for uptake and use by living plants. To increase soil microbes, incorporate organic matter into your soil for microbes to consume as food.


Confused about fertilizer numbers? A plant needs nutrients to survive. Most of these are provided by the soil, but soil varies tremendously in nutrient amounts, soil type, pH, and nutrient availability. The three main nutrients that have been identified as absolutely necessary for plants are nitrogen (N), phosphorus (P) and potassium (K).

These macronutrients are the source of the three numbers commonly found on fertilizer labels, which represent the percentage by weight of the N, P, and K levels found in the fertilizer (they are always listed in this order).

Nitrogen (N) is essential for the growth of stems and leaves. Chlorophyll, the green substance in plants responsible for photosynthesis, is largely composed of nitrogen. Nitrogen can be applied organically in many ways, including composted manure, blood meal, and bat guano.

Phosphorus (P) is important for the production of flowers, seeds, and healthy roots—used  more heavily during blooming and seed set. Phosphorus is easily rendered unavailable to plants when the pH is slightly unbalanced. It is released in soil through decomposing organic matter. Organic phosphorus can be found in rock phosphate, bone meal, and various liquid organic fertilizers such as fish emulsion.

Potassium (K), sometimes known as potash, is important for general health of plants. It is key in the formation of chlorophyll and other plant compounds. Potassium strengthens plants against cold, heat, disease, and pests, and it’s the key ingredient in fertilizers labeled as “winterizers.” Sources of organic potassium include Texas greensand, liquid seaweed, or kelp meal and compost. The potassium compounds in compost are water soluble, which makes them readily available to plants.

Organic Matter + Fertilizers = Happy Plants

Fertilizers are reliable, easy, and effective at supplementing essential soil nutrients. But, you cannot depend on chemical fertilizers alone to maintain soil fertility. An exclusive reliance on chemical fertilizers dooms the gardener to use ever-increasing quantities since the organic matter in soil is constantly declining.

In soil with low organic content, added fertilizer nutrients are quickly washed away and lost. Water soluble fertilizers make nutrients available to the plant immediately, but their effects are short lived. By supplementing your soil with compost and organic materials, you will naturally decrease your reliance on chemical fertilizers over time.

Expert Advice

To learn more about the various components of healthy soil, stop by the Garden Center or call 281-354-6111 to visit with our expert staff! We’re committed to sharing our love and knowledge of gardening with others. Warren’s Southern Gardens will get you growing!