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
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
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
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 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
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