PREPARE SOIL FOR FALL PLANTING
by Jerry Parsons, Ph.D.
Horticulture Specialist, Texas Agricultural Extension Service in San Antonio

Vegetable plant demise in July is attributable to natural catastrophes that occur in Texas, such as spider mites, squash bugs and temperatures over 90 degrees F. Vacations can also share the blame for the demise of many Texas gardens.

It is amazing how fast gardens decline without water and pest control! One week on vacation and encroaching bermuda grass shifts into a supernatural growth rate which be adequate enough to founder a herd of goats! Such invasions may not be of immediate concern, but fall garden preparation will necessitate detonation expertise to rid the area of the tenacious bermuda grass.

Vacationing gardeners fantasize that hordes of rampaging spider mites, suck flies and squash bugs will contract some social disease and become extinct. It won't happen, folks! Instead, those perverted pests will generate an incomprehensible multitude of garden terrorists that will play havoc with fall gardens.

The answer to these dilemmas is simple-garden sanitation. Instead of imposing on neighbors to maintain your struggling garden, give it to the garbage man! You may as well remove everything from the garden except okra. If you don't, the bugs will! Remember, when you "trash" your garden debris, you're not losing a garden, you're gaining freedom from the millions of pests for which you would have provided sanctuary otherwise.

This garden cleanup proposal generates groans and moans every year-"but my plants have tomatoes on them, my eggplants are beautiful". Now, there may be no fruit but you still think you have a beautiful plant. The dreams of coming home from a vacation to find large, luscious tomatoes hanging on healthy plants is a ridiculous fantasy! What you will find is a pest-infested plant with tomatoes smaller than when you left, and as hard as golf balls. Sentimentality about your spring garden is not worth it! Don't let the perils of July ruin the beautiful memory of your spring garden and its bounties-now gone but not forgotten.

Prepare for the fall success.

The first step in garden preparation is site evaluation. All vegetable produce their best in a full-sunlight situation. If your garden site does not receive at least 8 hours of direct sunlight daily you will not successfully produce those crops which produce seed-bearing fruit. These include tomatoes, peppers and eggplant. By "successfully produce" I mean tomato plants which will yield at least 15 to 20 pounds of fruit per plant. Greens (lettuce, collards, mustard) and root (carrots, beets, radish) crops tolerate shady conditions but do not excel.

If the selected site previously has been covered with grass, this turf must be removed. Don't think that you can dig or till this existing grass into the garden soil and get rid of it. Even a well-tilled, pulverized garden soil will contain enough Bermuda grass sprigs to cause troubles for years to come. New gardens are doomed before they begin if all bermuda and other lawn grass is not completely removed before tillage begins. If a raised garden is being considered, sod should be removed before additional soil is put into the prepared frame.

What about chemical applications to kill the grass, rather than pulling it out- Yes, you're in luck! There are several brand names which contain the weed killer glyphosate. These include Roundup, Kleenup, Doomsday and Weed and Grass Killer, Killzall. Check ingredients on the label for the term "glyphosate."

There are some grasses and weeds such as Bermuda grass and Johnson grass which resist pulling and hoeing -- they actually grow better the more you cut, pull and hoe! When used as directed, glyphosate-containing herbicides effectively control many weeds that other herbicides cannot control, and does it without adverse effects on cropping systems or the environment. The nutrient transport system of the plant is utilized for translocation from the plant foliage to the underground root or rhizome system. Symptoms of activity develop slowly, and weed damage may not be obvious for 2 to 4 days for annual plant species, and up to 10 days or longer for perennials. Visible effects are a gradual wilting and yellowing, which advances to complete browning and deterioration of plant tissue.

Glyphosate-containing herbicides are most effective when applied to the foliage of actively growing annual and perennial weeds or brush. Control of perennial weed species is most effective when applications are made at, or beyond, the early head or early bud stage of growth. Mowing or tillage operations should not be done prior to, or immediately after application, since sufficient time (3 to 7 days) must be allowed for translocation (absorption of the chemical and movement throughout the target weed). If weed foliage is removed or severely damaged during harvest, weeds must be allowed time to regenerate sufficient size to permit uptake and movement through the plant.

Upon contact with the soil, glyphosate is inactivated. The herbicide is tightly bound by the soil particles, preventing glyphosate uptake from soil by plant roots. This binding also prevents leaching and lateral movement through the soil. When applied to the soil at test rates 30 times the normal use rate, glyphosate-containing herbicides did not affect the growth of corn, soybeans and other crops, planted immediately after treatment.

While corn, soybeans and many other crops can be seeded immediately into established sods treated with glyphosate-containing herbicide, seeding of most crops should be delayed until the treated vegetation has died. Since glyphosate has no residual soil activity, it will not control weeds that emerge after application.

Application is not recommended when winds favor physical drift of a spray solution, or when rain is expected within 6 hours. The weed foliage should be dry and free of visible dust cover that could interfere with proper absorption of the herbicide. The formulation is non-volatile and will not damage any plant not contacted during application.

Some people claim that glyphosate "doesn't work" in the summer. Remember that proper translocation of the glyphosate molecule occurs only in actively growing weeds. Reduced control may result when treated weeds are not actively growing due to stress caused by drought, insect damage or disease. Although extremely cool or cloudy weather may delay visual symptoms of control, weed control is not reduced. If you don't want to use glyphosate- containing herbicides, a shovel and "elbow grease" is the next best solution. Remove 2 to 4 inches of sod to insure elimination of grass sprigs.

Once the sod has been removed, a new garden area should be shoveled to a depth of 10 to 12 inches. Roto-tillers, when used in a new garden area, will not penetrate adequately. Rototillers can be used to loosen and mix shoveled areas. Apply 1 to 2 inches of coarse (sharp), washed sand and 2 to 3 inches of organic matter to the garden site surface and incorporate to improve the soil's physical quality.

The soil's physical condition will have to be altered over a period of time rather than trying to develop desirable soil in a single season or 2. If you are making the effort to build a raised bed garden don't skimp on the amount of soil you use.

The addition of fertilizer is the next step. Care must be taken that excessive amounts of fertilizer are not used. Excessive fertilization can kill plants. Add 2 to 3 pounds of a slow-release, sulfur-coated lawn fertilizer (without weed killer, please!) per 100 square feet (10 feet by 10 feet). Use Ammonium sulfate every 3 weeks at the rate of 1 tablespoon sprinkled around each plant and watered in as a side-dress application for hybrid tomatoes and peppers. Animal manures may be substituted for commercial fertilizer and used at a rate of 60 to 80 pounds per 100 square feet of garden area.

Certain other ingredients should also be added to boost yields. The latest research indicates that the presence of available calcium prevents certain physiological disorders of vegetables as well as increases the efficiency of nitrogen uptake and stimulates growth. In the highly calcareous soil that we have in Texas, it is difficult to imagine that much of the calcium in the soil is not soluble or available for plant use. The best remedy for this situation, as well as a method of loosening these tight soils, is adding gypsum.

Gypsum (calcium sulfate) is a neutral product that will not cause our soils to become more alkaline. We surely don't want that! Gypsum, sold as Sof-N-Soil, or just gypsum, is recommended at the rate of 40 pounds per 100 square feet. Sulfur can also be added at the rate of 5 to 10 pounds per 100 square feet. It will slightly reduce the pH of the soil as well as forming its own gypsum as the sulfur combines with the soil calcium to produce calcium sulfate.

After all ingredients have been added, mix the soil thoroughly and prepare beds on which to plant rows of vegetables. These beds should be 30 to 36 inches apart to allow for easy movement through the garden area when plants get larger.