BED PREPARATION: Now that you have a plan, it's time to prepare areas for planting. Adequate bed preparation is probably the most important thing you can do to improve your chances of success in your garden. The principles described in this section apply to all kinds of planting, including turf grasses, shrubs, trees and vegetables.

Soil Amendments

Soils in Parker County vary widely, and include clay, sandy loam, caliche and rock. This means that many soils are not ideal for plant growth.

The best thing you can do to improve the structure for any soil, but especially clay soils, is to till or work in 3 to 4 inches of organic matter. What do we mean by organic matter? This can be almost any kind of organic material including peat, manure, mulch, compost, straw, hay, leaves, or grass clippings.

Peat moss is the most readily available material for soil conditioning. Peat in the soil creates favorable changes. It makes the soil more granular and more easily worked. It hastens the escape of excess water and, at the same time, absorbs and holds more water for plants. Peat allows more air to enter the soil, thus encouraging the growth of roots and microorganisms that help make plant nutrients more available. Most commercial peat moss is free of weed seeds and plant diseases.

Although peat contains some plant nutrients, it should not be considered a fertilizer. It is the long-term improvement in the soil's physical characteristics that make it valuable.

Results when using manure are less consistent because manure varies in nutrient value, degree of decomposition, and freedom from weed seeds and disease organisms. It contains more nutrients than peat, and its acidity is usually less. It will not last in the soil as long as peat. In some areas barnyard manure is readily available. Although nutrients are lost in aging, thoroughly rotted, old manure is much better for plants than the fresh material.

The greatest disadvantage of manure is the weed seeds that are often present. Composted or dried manure is more desirable since weed seeds and potential human pathogens have been killed, It is packaged for more convenient handling and often has plant nutrients added to bring it to a standard fertility level. Fresh manure should not be used except as a light top-dressing on beds. If used in this way it should not touch any plant stems or leaves.

Processed or rotted manure may be used in fairly large quantities as a soil amendment, mulch or top-dressing. Manure that has been rotted and exposed to weather may be used more liberally than the processed, bagged, dried manure. A layer 1 to 3 inches deep may be incorporated when preparing a flowerbed or lawn seedbed, while no more than 1 to 2 inches of the processed type should be used. Poultry manure contains greater amounts of nitrogen, and therefore should be used more cautiously than other manures.

Sawdust, wood shavings, shredded wood, pulverized bark and wood chips can be used to improve soils. In the raw or fresh state, these products are low in nitrogen. When they decay, nitrogen from the surrounding soil is used and the plants become starved for nitrogen. This can be prevented by the addition of nitrogen fertilizer to the material when it is mixed with soil or composted.

For best results, wood byproducts should be composted first before being added as a soil amendment. Very coarse wood products should be used only for mulching.

Sand has little water-holding capacity and no nutrient value; therefore, it is not recommended for use as a soil amendment. To be effective, 75 percent or more by volume of sand must be mixed into heavy clay soils before there is any improvement. Adding lesser amounts of sand can cause more problems, since sand mixed with clay are the ingredients of adobe. The missions in San Antonio show how long lasting such a mixture can be.

Because the majority of Parker County soils are slightly alkaline, lime should only be used if a soil test indicates that the alkalinity needs to be increased. Wood ash is also strongly alkaline, and should be used cautiously.

Pecan shells, corncobs and other fibrous agricultural byproducts are sometimes available for soil additives or mulching. Most of these materials will be good soil conditioners. In their coarse state, these materials are suitable for mulching.

Cottonseed meal has little soil conditioning ability, but it is a good organic fertilizer. It contains from 6 to 10 percent nitrogen, and is useful as a side-dressing for many ornamental plants and vegetables.

If your soil is very heavy clay (or rock), you may wish to consider building raised beds on top of the soil. Bring in 6 to 8 inches of good, screened sandy loam topsoil to provide a better growing space for your vegetables and ornamental plants. Also available from local sources is a mixture of topsoil and compost, which makes excellent beds.

Beds can be constructed of brick edging, masonry or rot-resistant timbers and filled with soil previously combined with organic matter and nutrients. Low mounds of soil without edging (a berm) can also be used to add several inches of desirable soil.

There is one other option that can be used to help with clay soils. Research indicates the addition of expanded shale can improve clay soils. It is marketed locally by TXI under the name TruGro,

Dr. George recommends putting down 3 inches of expanded shale on top of the area, and tilling it in 6 to 8 inches deep. In addition, add 3 inches of finished, plant-based compost, which results in a 6-inch raised bed.

Dr. George stated that due to its porous nature, expanded shale provides aeration from within and, in poorly aerated clay soils, results in an extensive and healthy root system.


Compost is very beneficial for soil improvement. It offers many of the same features as manure and may be used at the same rates. It can be used in potting soil, in the preparation of flowerbeds and gardens, and as mulch for trees and shrubs.

Composting is a process to turn organic matter into a soil conditioner called compost or humus. Chopped straw, leaves, grass clippings, weeds and other plant refuse may be composted.

To start the compost heap, place a 6 to 8 inch layer of plant materials in a well-ventilated bin. Moisten these materials, but do not soak them.
Use a mix of dried and fresh plant refuse to achieve a good carbon-to-nitrogen ratio. If green (high nitrogen) plant materials are unavailable, use manure or commercial fertilizer as a nitrogen source. Sprinkle 1 cup of a high nitrogen garden fertilizer for each 25 square feet. The layer should then be covered with 1/2 to 1 inch of soil.

Use several layers to complete the heap. Keep it moist but not soaking wet. Make the top of the heap flat or slightly depressed in the center so that rainfall can soak in. During warm weather, the pile should be turned approximately every month, but during the winter months turning will not be necessary. It will take 4 to 6 months for the materials to decompose thoroughly, depending on the frequency with which the compost heap is turned.

From the real dirt A Gardening Handbook for Parker County: