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Creating A Butterfly
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January Citrus Clinic
A B O U N T I F U L G A R D E N
Tomatoes in the Desert Garden
by Laurel Reader,
It was once known as the Peruvian Apple, in France it was named the love apple, and in Italy it was known as
pomodoro-the golden apple. Our name, tomato, comes from the ancient
Nahuatl name tomatl.
Wild forms of the tomato originated in South America in areas of the Andes
Mountains, and were brought to Central America and Mexico by prehistoric
Indians. They were introduced to Europe in the 16th century, supposedly
by Columbus, although at the time tomatoes were grown for ornamental
purposes and were considered poisonous. The tomato plant was brought to
North America in the early 18th century, but was not accepted as a food
plant for another 100 years.The fruit began to gain popularity in America
with the growth of the Campbell Soup Company after its commercial canning
factory opened in 1869. It is now the third most popular commercial vegetable
and the single most popular home garden vegetable in the U.S.
Interestingly, the tomato did not appear in Chinese cooking until the
last quarter century.
Although botanists classify tomatoes as fruit, the U. S. Supreme Court ruled to
apply vegetable tariffs on them in 1893. By the early 1900s, the USDA began
breeding tomato cultivars to develop specific characteristics such as disease
and pest resistance, cold and heat tolerances, salt and drought tolerances,
and uniform ripening. Unfortunately, by the 1950s, the hybrids coming on
the market were being bred for shipping date and not
for taste. Lucky for us though, there are so many varieties now being produced
we can find tomatoes that grow in
just about any climate or condition-
even the arid desert!
Tomatoes are members of the nightshade family,
Solanaceae , which means their leaves are toxic and should
not be eaten. They are a warm-season perennial plant, usually grown as
annuals. We have two short growing seasons here in the desert: March
through June, and again from September through November. Most plants yield an average of 10 to 15
pounds of fruit.
Tomato plants are classified as either determinate or indeterminate types.
Determinate plants are usually bush types that mature to a size of 3 to 5
feet, set fruit, and then decline. Although most have early-maturing
fruit, determinate plants do not produce for extended periods.
Indeterminate types are generally vining plants that grow until frost or disease
kills them. They require some support to keep the fruit from sitting in
damp soil, and they produce larger crops over a longer period. With the
right conditions and care, these plants can produce fruit for two or three seasons
before they lose vigor and production decreases.
Tomatoes range in size, color, and shape-from bite-sized cherries to the
2-pound Bigboy. Colors include pink, yellow, orange, purple, striped, and
even black. Depending on the variety, they can be rounded, oblong, or pear-shaped.
CHOICES FOR THE DESERT
When considering choices of cultivars for our climate and growing seasons,
consider earliness or maturity (how soon the fruit can be harvested after
planting out), adaptation to our climate and soil conditions, and also disease
and pest resistance . Remember, we are not looking for large tomatoes here, but
quality tomatoes. Larger types of tomatoes require more time for ripening, so
it's best to plant the small and medium-sized varieties in our desert gardens. Look for tomatoes labeled for 60-
to 70-day maturity. Successful varieties include: Yellow Pear, Cherry, Sweet 100,
Earlypak, Earlygirl, Small Fry, Patio, Champion, Earliana, and Sunripe. When looking for resistant varieties,
the letters "VNFT" indicate a plant's resistance to Verticillium Wilt (V),
Nematodes (N), Fusarium Wilt (F), and Tobacco Mosaic Virus (F).
HOW TO GROW
January is the month to start thinking about planting your tomatoes. Since
transplants can be set out as early as February 15, now is the time to decide
whether you will start with seed or container plants from the nursery. The time
required to germinate seeds and grow seedlings large enough for transplanting
ranges between 6 and 8 weeks. Nursery transplants require less work and time
on your part, but seeds provide a much larger selection of tomato types.
When starting from seed, select containers with good drainage. Peat pots
work great because they can be planted directly in the ground after scoring
their sides. Fill the containers with a light to medium soil mix, and then add
enough water to settle the soil until water drains from the bottom of your
containers. Use your finger to indent the soil to a depth of 1/4 to 1/2 inch.
Place 2 or 3 seeds in each hole and lightly spread soil over the seeds without
tamping. Sprinkle with a little more water, just enough to ensure good seed
contact with the soil. Placing clear plastic containers over the top of the pots
creates a mini greenhouse, but this is not necessary if you have a warm, sunny
windowsill where you can remember to monitor soil moisture.
The containers should receive at least 6 hours of good sunlight daily. It is important to
keep the soil moist, but not soggy, through the germination period. Usually a few sprays with a misting
bottle 3 or 4 times a day is sufficient, but never let the top 1/2 inch of soil dry
out. Germination usually occurs within 10 days. A week after the first true leaves break through the soil, thin each
container to one plant by gently pulling the weaker seedlings at the soil line. Change the method of watering to a
deeper, less frequent, application remembering that the soil should
remain on the moist side, but should not stay soggy. Turn the plants occasionally
to allow them to receive even sunlight all around. Once your plants
are about 2 inches tall, you can begin to fertilize by adding a diluted fertilizer
when watering. One teaspoon to a half-gallon of water is recommended. In about 6 weeks, your plants should
be 4 to 6 inches tall and ready to be planted out if temperatures allow.
Before planting however, it is best to harden off the plants for a few days by
setting the containers outside in a well protected area. They should be protected
from too much wind or sun, and if the nights are expected to drop below
60 degrees, you should bring the plants inside again until morning.
Optimal conditions for planting tomatoes in the desert garden include the
right location, p roper soil preparation, and favorable temperatures. Sunlight is
essential to tomatoes, so locate your garden in an area that receives a minimum
of 6 hours daily, preferably morning sun. The east side of your home or
other large structure is ideal. Otherwise, consider planting your garden in an
area where larger growing plants (sunflowers, corn, etc.) can be utilized to
shade your tomatoes during the hottest part of the day. Building a frame on
which to attach shade cloth is another excellent way to protect your fruit once
the weather starts getting hot.
Prepare your site early by tilling soil to a depth of 2 to 3 feet. Incorporate composted
manure, ammonium phosphate and soil sulfur into the planting area. Remember that feeder roots of tomato
plants range from 2 to 4 feet, so be sure to mix the backfill and amendments
thoroughly and deeply. Water the planting area, then wait two weeks and
water again. Wait at least one more week before planting so the soil is not
Once the soil is ready, your new plants have hardened off, and soil temperatures have reached 60 degrees, it's
finally time to plant! When planting in the cooler months of February and
early March, consider planting young transplants on their sides in 2- to 3-
inch trenches where the soil is warmest. Remove all but the top 2 to 4
sets of leaves from each plant, lay plants in individual trenches about 24
inches apart, and bury all but the leafy part of the plants. The stalks will produce
new roots and give new plants a better start. New vegetative growth will
reach upward toward the sun within a few days.
Tomatoes should be bottom-watered (water the roots, not the leaves). Soil-borne diseases can cause problems if
water splashes up from the soil to the leaves. Soil should remain moist, drying
slightly between waterings, but it should never be allowed to dry completely, nor should it remain too soggy.
Water deeply (2 to 3 feet) once a week during the cooler weather and increase
watering to 2 or 3 times a week in the summer. Mulch heavily with organic
material to help maintain and moderate soil moisture. Watering is most critical
when plants are producing flowers and fruit.
Fertilize plants with diluted fertilizer every 2 or 3 weeks until flower and
fruit production begins. No additional fertilizer should be re q u i red until plants
have completed fruit production. Avoid late and excessive applications of nitrogen. Too much nitrogen stimulates
unnecessary vegetative growth and delays the fruit from ripening. Keep the
surrounding area weed-free.
To aide in flower pollination, shake plants lightly each day after flowers
appear. Generally, it is said that flowers do not set fruit when temperatures are
below 55°F or above 90°F. However, I have had abundant tomato production
all summer long when growing smaller varieties, cherries and yellow pears, in
heavily mulched soil under 50% shade cloth. Indeterminate plants that have
stopped or slowed production in the hot summer temperatures will often
become productive again when the weather cools in September and
October, so don't give up on them when they look half-dead in August!
PESTS AND DISEASES
A common pest is the tomato hornworm. You may also see tomato fruit
worms (also known as corn ear worms), cutworms, flea beetles, spider mites,
and aphids. Microscopic root-knot nematodes can enter the root tissues,
affecting the transport of water and nutrients. Caterpillars (worms) can be
handpicked and disposed of, or the leaves of plants can be sprayed with
Bacillus thuringiensis (Bt), a product that only affects caterpillars. Many other
pests can be controlled with insecticidal soap spray. Root-knot nematodes can
usually be prevented by proper crop rotation, or solarizing the garden bed
using a clear plastic cover in the summer months to kill pathogens located in
the top 12" of the soil.
Common diseases include Fusarium Wilt, Verticillium Wilt, Curly Top, and
blights. To prevent Fusarium and
Verticillium wilts, select resistant varieties. Use floating row covers or shade
cloth to prevent leafhoppers from spreading Curly Top and other viruses
from host plants.
Other problems include sunscald, leaf roll, wilting, cracks in fruit, and blossom-
end rot. These are usually related to our heat and are worsened by poor
watering practices. Using a 50% shade cloth and correcting the method of
watering should solve these problems. Blossom-end rot is believed to be due
to a calcium deficiency that may be the result of irregular watering even though
there may be an abundance of available calcium in the soil.
Wait for fruit to ripen on the vine whenever you can. For red fruit types,
wait until a deep red uniform color is achieved. For the best flavor, pick just
before use. Cut fruits from the plant; do not pull them off. If picked while green,
tomatoes can be ripened in a paper bag containing a banana or apple.
Tomatoes can be dried, canned, or frozen. The best tomatoes for drying are
paste tomatoes, such as Romas. Juicier, less meaty, tomatoes can also be dried;
they just take a little longer. Although we can dry tomatoes outside in the sun
since our summers are so hot, I prefer a food dehydrator because it's quicker
and I don't have to worry about insects. The fruit can also be dried in a warm
oven at about 150 degrees for 10 to 15 hours. (Actual time depends on the
thickness and variety of the tomato). When fully dried, no pulp should be
sticky or tacky to the touch. Store dried tomatoes in airtight containers in a
cool, dark, dry place or pack them with olive oil in a sterilized jar. You can add
herbs or garlic cloves at your option.
Ripe tomatoes can be frozen whole. Place them in a plastic bag, pushing out excess air from bag, and seal tightly.
When thawing frozen tomatoes, place them in water (at room temperature) and the peels will come off easily. You
can also freeze tomato sauce, salsa, or puree in airtight plastic bags or containers.
While many people find that freezing is easiest, canned tomatoes taste better. The
process uses heat to pack
tomatoes or sauces in high-vacuum
jars as it removes oxygen, destroys enzymes, and prevents the growth of
bacteria. Flavor stays in and microorganisms stay out. Canning involves
much more work, but it's worth it.
Tomatoes are considered one of the best
health foods in the American diet. They
are packed with vitamins and minerals. One cup of cherry tomatoes contains
approximately 31 calories, 7 carbohydrates, and only 0.5 grams of fat.
References and additional information:
Brookbank, George. 1991.
Desert Gardening: Fruits and Vegetables, The Complete Guide.
Cromell, Guy, & Bradley. 1999.
Desert Gardening for Beginners.
Arizona Master Gardener Press.
McMahon, Kofranek, & Rubatzky. 2002.
Hartmann's Plant Science. 3rd Ed.
Owens, Dave. 2000.
Extreme Gardening, How to Grow
Organic in the Hostile Deserts.
Poco Verde Landscape.
Siegel, Helene. 1996.
The Totally Tomato Cookbook.
Celestial Arts Publishing.
Photography: Copper Bitner
Maricopa County Master Gardener Volunteer Information
Last Updated January 25, 2003
Author: Lucy K. Bradley, Extension Agent Urban Horticulture, University of Arizona Cooperative Extension, Maricopa County
© 1997 The University of Arizona, College of Agriculture and Life Sciences, Cooperative Extension in Maricopa County
Comments to Maricopaemail@example.com 4341 E. Broadway Road, Phoenix, AZ 85040,
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