In last week’s column were seed sources from Texas companies. As gardeners plan plots for spring gardens, the main absolute as we plant seed is soil preparation.
Soils in our growing area are deplete in organic matter, which means that the number one consideration in improving garden soils is the addition of organic matter. Soils with adequate organic matter will be friable (loose and crumbly), drain well, have increased aeration, and be a reservoir for nutrients, minerals and microorganisms.
Friable soils have small soil aggregates that easily break apart. Contrast these soils with little to no organic matter that have large clods that are difficult to separate, almost like bricks. Contrast friable soils with compacted soils. Compacted soils have reduced pore space (see below in aeration) that affects water movement.
Soils that drain well have the characteristic of maintaining soil moisture without puddling or pooling. Water easily percolates through soil particles, a critical component in soil aeration.
Aerated soils are absolutely essential in providing the conditions needed for optimum root growth. All soils have a mixture of soil particles and soil pores, the space created between the particles. Soils with too large soil pores will drain too quickly, with little water retention; conversely, soils with too small pore space are those that do not drain well, restricting the oxygen and carbon dioxide exchange between soils and atmosphere. Increasing pore space allows for the gas exchange necessary for root development.
Soils high in organic matter are reservoirs for the nutrients and minerals that are released into the soil during the decomposition process of the organic matter. Microorganisms facilitate the decomposition process; without microorganisms the organic matter would not decompose. Soil microorganisms include beneficial bacteria and fungi. Organic matter used as soil amendments should be clean of weed seeds and diseases. Good sources of organic matter are well-composted manure, shredded leaves, pine needles, and straw. Incorporate the organic matter by tilling into soils several months before seed sowing, allowing time for the decomposition process. A good barometer of the level of organic matter is the presence of earthworms.
Mulch bare soil by spreading organic matter evenly on the surface of the soil; add a layer several inches thick. Over the winter or in a few months microorganisms and earthworms will use the organic matter as a carbohydrate food source, gradually diminishing the thick layer.
Ellen Peffley Harp, a retired professor of horticulture at Texas Tech University, writes about gardening for several Texas newspapers.
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