COMMON SPRING GROWING PROBLEMS
by Jerry Parsons, Ph.D.
Horticulture Specialist, Texas Agricultural Extension Service
in San Antonio
Folks are CRITICALLY UPSET at this time of the
Things are going wrong with their precious plants.
I guess that people thought that all there is to growing plants
in Texas is planting them and waiting for a bountiful harvest.
The most common disaster is yellowing plant foliage. This
affects everything from gardenias to beans, and peas to photinias
(for some reason folks do not want yellow - tipped photinias!).
The answer to this yellowing condition is iron chlorosis,
or the lack of sufficient iron that the plant can use. The
condition is endemic to this area of Texas. The soils here
contain huge quantities of calcium carbonate (lime) which
cannot be easily neutralized.
What is the answer to this dilemma? The best
answer is to plant only recommended, adapted (to local soil
conditions!) plants. There is a list of such plants for every
and specifically for South Central Texas at:
You WILL NOT find such plants as azaleas, dogwood
trees, gardenias, loblolly pines, muscadine grapes or any
of those Southeastern plants on the list for South Central
Texas. Folks who insist on planting such problems-waiting-to-happen
should realize that sooner or later the "old yellow"
syndrome will occur. When non-adapted plants are small, a
micro-environment modified with peat moss can enable the plants
to survive for a brief period of time in a seemingly healthy
condition. But sooner or later, the alkaline water and alkaline
soil will provide an inhospitable environment and the plant
will turn yellow, leaves will exhibit the severe iron chlorosis
symptoms of browning around the edges of the leaves and will
eventually weaken and die.
I have recommended the use of organic matter (leaves, grass
clippings, etc.) and compost in vegetable gardens. Mulching
around "problem" trees and shrubs can also alleviate
the situation. Any organic material can and should be used
as a mulch around established plants.
If huge quantities of non-decomposed organic
material is used, additional amounts of nitrogen fertilizer
will have to be added to compensate for nitrogen use during
decomposition. Maintain a 3- inch mulch around plants to help
control weeds and grass, stabilize soil temperature and conserve
moisture. Do not apply mulch directly against plants. "Artificial"
remedies, such as copperas (iron sulfate) and iron chelates
(Sequestrene) furnish an available iron source for plants
and can also be used to correct the yellowing problem.
Growers may as well accept the fact that this
problem is here
to stay because of our alkaline soil conditions, and should
treat it accordingly each year. Plants will exhibit symptoms
of "iron deficiency"- with yellow leaves and darker
green veins. This condition will only grow worse and the affected
plant will decline and die if not corrected with generous
quantities of iron sulfate mixed with organic material. Alkaline
soils in this area of the state require frequent summer applications
of iron-containing products to correct or prevent iron deficiency
of plants. The products Ironate (has supplemental nitrogen)
and green sand seem to be effective. Mulches can be used to
increase the availability of iron for plant uptake in the
soil by making a synthetic iron chelate. If iron is applied
directly to the soil, calcium in the soil causes the iron
particles to be unavailable for plant uptake. Gardeners can
make a synthetic chelate with mulch by mixing one cup of iron
sulfate (copperas) to each bushel of mulch applied. Iron particles
will adhere to the surface of the mulching material and will
be released to the plant as decomposition occurs around plants.
Iron sulfate treated mulches are also effective when incorporated
into the soil. Iron sulfate (copperas) or chelated iron as
a foliar spray can provide a rapid-but-temporary green-up.
Bloom drop is also causing concern this time
of the year. Whether the blooms are tomato, beans, squash,
or pepper, what can be more disastrous after all your hard
work than losing the plant's producing potential? The problem
is the plant's environment-both existing and imposed. The
imposed bloom-drop environment involves those folks who have
chosen to ignore the FIRST COMMANDMENT OF SUCCESSFUL GARDENING
and planted in the shade.
If you cannot sunbathe in your garden area
for 8 to 10 hours daily, then DO NOT expect maximum yields
from tomatoes. Some vegetable crops tolerate shade but none
produce to their optimum in the shade. If your plants grow
tall and spindly and drop blooms, then you have the plant
growing in too much shade!
Another problem may be variety selection. Some
indeterminate varieties such as Big Boy, Better Boy, Beefmaster
and other ridiculously large-fruit varieties drop early blooms
profusely. Recommended tomato varieties for large fruit types
include Heatwave, SunMaster and Surefire. Such recommendations
are based on at least 3 years of field tests including spring
and fall conditions.
Tomato blooms leave such a pronounced stem
when they fall from the bloom cluster that many gardeners
think the blooms have been eaten by insects. Some of this
poor fruit set can be caused by cloudy weather conditions
and its direct relation to improper pollination of blooms.
Tomato flowers are pollinated by either wind or mechanically
so gardeners don't have to have bees. Sticky pollen caused
by cloudy, damp weather conditions cause a lack of pollen
shattering and, consequently, poor pollination.
Since we are discussing such sensual topics
as pollination and fertilization, we may as well deal with
the subject of squash. Is everyone upset about their squash
blooms falling off? Are the falling blooms of the male or
female gender- What? You don't know the difference? I will
try to explain the difference even in fear of censorship.
To begin with, there are male blooms and female blooms. The
female blooms can be distinguished from male blooms by the
fact that they have a small squash fruit attached. All of
the males, which bloom profusely at first, will dry up or
fall off. This is true for pumpkins, cucumbers, and watermelons.
Any further lessons in sexology can be arranged by appointment
When male and female blooms are both present,
and female blooms with small fruit attached continue to fall
off, then you have a pollination problem. Pollination means
the transfer of male parts to the female part. This task usually
is accomplished by bees or insects visiting the flowers. If
you don't have a source of such pollinating insects, or continually
kill them by spraying insecticides during flight periods,
inadequate pollination and fruit drop will occur. During peak
pollination seasons, spray insecticides late in the afternoon
to avoid problems.
If you do not have bees, you can hand-pollinate
blooms. This involves taking a male bloom, removing the petals
and rubbing the stamen (the pollen-containing male part) in
a female bloom early in the morning, before 10am. This will
effectively transfer the male pollen to the female bloom.
I told you gardening could be fun and exciting!
Squash sex may not be the only issue creating
production problems. Planting in the shade will cause lack
of fruit set, as will overwatering. Water plants growing in
sandy soil more often and with a lesser amount. Check the
soil around plants by digging with your finger to determine
if moisture is present. If moisture is present, DON'T WATER!
REMEMBER -- MORE PLANTS ARE KILLED BY OVERWATERING THAN BY
NOT ENOUGH WATER. Don't try to "hurry" plants into
production with excessive watering; all you are accomplishing
is the "hurrying" of plants to death.
These are a few of the "growing"
problems that many gardeners are experiencing. There will
be more--after all, if growing vegetables was easy, everyone
would be a vegetable farmer. When the blooms are dropping,
the fungus is attacking, and the insects are rampant, just
be glad that your garden is 10- feet wide and 10- feet long
and not 400 acres!