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The soil for warm-season crops should be prepared during July or at least two weeks before planting. The soil may too hot for planting unless you provide some shade and deep mulch.
The crops to plant in the waning days of July are eggplant, melons, okra, Southern peas and pumpkins. Other crops that may be planted from now into August are sweet corn and summer squash (until Aug. 20), cucumber (through Aug. 15) and winter squash (through Aug. 10).
The soil determines plants' health, growth and production. Ideal soil is a complex mixture of mineral elements (45 percent), organic matter (5 percent), air (25 percent) and water (25 percent) for most garden and landscape plants in this area. Then there are the pH (acid, neutral or alkaline), and the soil types (clay, loam or sandy) to consider, too.
The presence of mature earthworms in soil indicates excellent soil conditions for crops, and following is a look at desirable physical and chemical properties.
Physical properties
Physical properties of the soil are visible but may not be easy to improve. The best soil is crumbly (friable), so a plant's roots, water, air and fertilizer elements can penetrate more easily. Soil type determines texture and how easy it is to till.
Clay soil may be softened with gypsum and organic matter. The fertility of sandy soils may be improved with organic matter.
Gardeners can prevent compaction by not walking on the soil (plant in 2-, 3- or 4-foot-wide raised beds), minimizing cultivation, not tilling when it is wet and letting the soil lie fallow once every several years.
Chemical properties
Chemical properties are not visible, but they must be suitable for plants' health, growth and production.
The pH is a logarithm scale that measures the acidity (0 to 6.9), neutrality (7) or alkalinity (7.1 to 14) of the soil and water. The pH is a major controlling factor affecting roots' ability to absorb nutrients.
Each plant species has its preferred pH range of soil/water. Most garden plants are 6 to 6.8 pH; most landscape plants, 5.5 to 7 pH; and acid-loving plants (azaleas and gardenias, for instance), 4 to 5.5 pH. The pH range for crape myrtles is 6.5 to 7.5; for tomatoes, 5.5 to 7.5.
Chemically, sulfur amendments applied will lower the pH, and limestone applied will raise the pH.
Compost, peat moss and shredded bark applied will lower the pH. The local water and clay soils are alkaline. The amendments must be mixed into the soil well but still may require a year or so to become completely effective.
The major elements (macronutrients) nitrogen, phosphorous, potassium, calcium, magnesium and sulfur are in the soil. The minor elements (micronutrients) iron, zinc, molybdenum, manganese, boron, copper and chlorine are in the soil. The carbon, hydrogen and oxygen are in the air and water.
The roots absorb 98 percent of their nutrients from the soil after they are dissolved in the soil moisture. Foliar feeding is usually only a 2 percent effective method to fertilize plants.
If your garden didn't develop a bumper crop of vegetables, it's time to have soil samples analyzed. Samples should be taken when no crop is growing. They should represent the problem area and be taken from the surface to the depth of the root zone of the next crops.
Do not disturb the soil if it is so wet that it sticks to you and your garden tools, because you'll compact it.
You may also wish to analyze subsoil samples. After obtaining a topsoil sample, place the probe into the same hole and push it down to 16 to 24 inches deep for the subsoil sample.
For detailed information about soil testing, contact Brazos County AgriLife Extension, 2619 Texas 21 W. in Bryan or call 823-0129.
Future columns
My Home Grown columns in The Eagle will appear only the second and fourth Fridays of each month starting Aug. 1. My columns will alternate with Charla Anthony's Garden Sense columns, which will be in The Eagle the first, third and fifth Fridays of each month.
• Write to Elmer Krehbiel, Master Gardener, c/o Brazos County Office, Texas AgriLife Extension Service, 2619 Texas 21 W., Bryan, Texas 77803. His e-mail address is elmer.krehbiel@theeagle.com.
