UNIVERSITY OF CALIFORNIA
Division of Agriculture and Natural Resources
http://anrcatalog.ucdavis.edu
Publication 7228
PROCESSING TOMATO
PRODUCTION IN CALIFORNIA
TIM HARTz, Extension Vegetable Specialist, Department of Plant
Sciences, University of California, Davis; and GENE MIyAO, JAN
MICkLER, MICHELLE LESTRANGE, SCOTT STODDARD,
JOE NUñEz, and BRENNA AEGERTER, University of California
Cooperative Extension Farm Advisors
PRODUCTION AREAS AND SEASONS
Processing tomatoes (Lycopersicon esculentum Mill.)
are grown in the San Joaquin and Sacramento Valleys,
with production centered in Fresno, Yolo, San Joaquin,
Kings, and Colusa Counties. Significant produc-
tion also occurs in Merced, Stanislaus, Solano, and
Sutter Counties. Fields are planted from late January
through early June for continuous harvest from late
June into October. California accounts for over 90 per-
cent of U.S. production and approximately 35 percent
of world production.
PROCESSING TOMATO ACREAGE,
yIELD, AND VALUE
Year Acreage Average yield per acre
2004 281,000 41.5
2005 267,000 36.4
2006 283,000 35.8
Source: USDA National Agricultural Statistics Service,
http://www.nass.usda.gov.
CLIMATIC REQUIREMENTS
Tomato is a warm-season crop that is sensitive to frost
at any growth stage. The optimal soil temperature for
seed germination is 68°F (20°C) or above; germination
below 60°F (16°C) is extremely slow. Daily maximum
air temperature between 77°F and 95°F (25° to 35°C)
is ideal for vegetative growth, fruit set, and develop-
ment. With adequate soil moisture, tomato plants can
tolerate temperatures well in excess of 100°F (38°C),
although fruit set can be adversely affected. Fruit
development and quality are severely reduced when
day and night temperatures fall below 68° and 50°F
(20° and 10°C), respectively.
VARIETIES AND PLANTING
TECHNIQUES
Processors conduct extensive evaluations to identify
varieties with appropriate characteristics for specific
end products. Production contracts require growers to
select from a list of approved varieties chosen by the
processor. Growers select varieties from this list based
on yield potential, earliness, and nematode and dis-
ease resistance. Hybrid varieties are now planted in
nearly all fields. Dozens of varieties are commercially
grown in California. The five most commonly grown
varieties in 2005 were AB 2, Heinz 9780, Heinz 9557,
Halley 3155, and Hypeel 303; these varieties consti-
tuted more than 60 percent of California production.
Since 1990 the trend has been from direct seeding
to transplanting; the majority of tomato fields are
now transplanted. Transplanting simplifies seedbed
preparation and stand establishment, reduces weed
competition, provides more options for weed control,
and reduces hand-weeding expense.
To accommodate wet soil conditions in the spring,
beds are generally made in the fall, allowing for
timely planting and reduced soil compaction. Ground
preparation prior to listing beds includes subsoiling,
disking, and landplaning. Growers are increasingly
experimenting with various approaches to reduce
tillage, driven by the desire to reduce tillage costs and
improve profitability. These alternative approaches
vary from simply combining multiple operations into
one equipment pass to minimum tillage schemes in
which some operations are eliminated. Winter-grown
cereal or legume cover crops preceding processing
tomatoes can improve soil tilth and provide a “rota-
tion” for fields in which tomato is planted in succes-
sive years. Despite these potential advantages, cover
cropping remains an uncommon practice due to the
Vegetable Production Series
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costs involved and the difficulty of incorporating
cover crop residue in wet spring weather.
In the San Joaquin Valley 66-inch (1.7-m) beds are
common, while in the Sacramento Valley 60-inch
(1.5-m) beds are the norm; beds are planted with
either a single or double row of plants. Seeding rates
are usually 40,000 to 60,000 seeds per acre (100,000
to 150,000 per ha), with a desired final plant spacing
of 2 to 3 plants per clump 9 to 12 inches (22.5 to 30
cm) apart in the seed line. Mechanical and precision
vacuum planters are used to meter seed. Tomatoes
can compensate for thin stands, with gaps up to 30
inches (75 cm) between plants causing only minor
yield loss. Seeding depth varies from 0.5 inch to over
1.5 inches (1.2 to 3.7 cm), depending on soil charac-
teristics. Seedling emergence may require more than
30 days under cool soil temperatures. Under soil tem-
peratures in the 80°F (27°C) range, emergence occurs
within 7 days of planting.
Transplants are custom-grown by commer-
cial greenhouse operations and are delivered to the
field as plug plants seeded in trays. Transplants are
mechanically planted into fields starting in early
March and continuing until early June. Both mechan-
ical finger type, hand-fed transplanters and carousel,
rotary transplanters are commonly used. Automated
systems are being evaluated. Transplant populations
of single- or double- seeded plugs are typically 7,000
to 9,000 per acre (17,300 to 22,200 per ha). Water, usu-
ally containing N and P fertilizer, is often applied at
transplanting at rates up to 400 gallons per acre (3,745
l/ha). Alternatively, a pre-transplanting fertilizer
application to the soil is also common.
Mechanical cultivation operations help control
weeds, minimize large clods on the bed surface,
and maintain deep furrows and a smooth, slightly
crowned bed surface to facilitate mechanical harvest.
A mechanical vine trainer is often needed to push
vines out of the furrow onto the bed, or a mechan-
ical cutter is used to trim excessive vine growth.
Maintaining an unobstructed furrow increases furrow
irrigation efficiency and provides better fruit recovery
at harvest.
SOILS
A variety of soil textures are used for processing
tomato production. Sandy soils are preferred for early
planting because they can be planted sooner during
wet weather and warm more rapidly in the spring,
promoting seed germination and early growth. Loam
and clay loam soils are generally more productive
than sand. Clay soil may be used, provided it is well-
drained and irrigated carefully; Phytophthora root
rot, a soilborne fungal disease, can be a serious prob-
lem in heavy soils with excessive soil moisture.
IRRIGATION
All processing tomatoes are irrigated. Sprinkler irri-
gation is used primarily for stand establishment,
although a few growers use sprinklers throughout the
growing season. Furrow irrigation is the most com-
mon irrigation technique employed after stand estab-
lishment. Irrigation frequency varies widely by grow-
er, soil type, and growth stage; 7- to 14-day intervals
are typical. It is a common practice to cut off irrigation
2 to 4 weeks before harvest to enhance the soluble
solids content of the fruit, reduce the risk of fruit rots,
and minimize soil compaction from mechanical har-
vest operations.
The use of drip irrigation is increasing substantially
each year; currently more than 20 percent of process-
ing tomato acreage is under drip management. Drip
irrigation generally increases yield and allows effi-
cient irrigation of fields that, because of slope or soil
characteristics, are difficult to irrigate by other means.
Also, in a large area of the San Joaquin Valley the pres-
ence of a shallow, saline water table complicates irri-
gation management. The use of drip irrigation in this
area maintains productivity by keeping the root zone
relatively salt-free, and the high efficiency of drip irri-
gation minimizes the volume of drainage water gen-
erated. The typical drip system employs a single drip
tape buried 8 to 12 inches (20 to 30 cm) deep in the
bed center, although the use of surface drip systems
(in which the drip lines are laid in the furrows after
crop establishment) is becoming increasingly com-
mon. Sprinkler irrigation is often used for transplant
or seedling establishment, with drip irrigation begin-
ning around first bloom. Drip irrigation requirements
are determined by weather-based reference evapo-
transpiration (ETo) estimates and crop growth stage;
irrigation frequency may vary from once or twice a
week early in the season to daily irrigation during
periods of peak water demand. Some growers reduce
irrigation in the final 4 to 6 weeks of the season to
increase fruit soluble solids concentration.
FERTILIzATION
Fertilizer application rates vary widely among
California tomato growers. Typical seasonal applica-
tion rates are 125 to 250 pounds of nitrogen (N) per
acre (140 to 280 kg N/ha), 40 to 120 pounds of P205
per acre (20 to 60 kg P/ha), and 0 to 200 pounds of K20
per acre (0 to 185 kg K/ha). University of California
research has shown that under normal conditions,
maximum yield can be obtained with approximately
100 to 150 pounds of N per acre (112 to 168 kg/ha),
and even less in fields with substantial residual soil
nitrate from prior cropping. Soils with bicarbonate-
extractable phosphorous (P) greater than 20 ppm
are unlikely to respond to P application, although a
2 • Processing Tomato Production in California
temporary early growth response to preplant P may
be seen in early spring conditions. Below 15 ppm,
a yield response to applied P would be expected.
Many California soils have adequate potassium (K)
for high-yield tomato production. However, on soil
with ammonium acetate-exchangeable K less than 150
ppm, K application may be required; seasonal K rates
seldom exceed 200 pounds of K20 per acre (185 kg K/
ha). Fruit color uniformity is an important quality
factor for peel/dice processing. A common disorder
called yellow shoulder, in which the tissue surround-
ing the stem scar remains yellow after fruit ripening,
is encouraged by K deficiency. Although K fertiliza-
tion in excess of that required to maximize yield may
reduce the incidence of yellow shoulder, such applica-
tions are usually not economical.
Micronutrients are seldom deficient in the mineral
soils of the San Joaquin and Sacramento Valleys. Zinc
deficiency does occur and is normally corrected by
including zinc with the preplant macronutrient fertilizer.
Gypsum is commonly applied as a soil conditioner to
improve soil structure and water infiltration but seldom
for its nutrient value since most California soils have
sufficient calcium and sulfur to meet plant requirements.
Regardless of irrigation method, most P is applied
preplant or at transplanting. Where drip irrigation is
used, most N and K (if needed) are applied by ferti-
gation throughout the season. In conventionally irri-
gated fields, N and K (if needed) are applied preplant
or at planting, and in one or more sidedressings; late-
season water-run application may also occur.
INTEGRATED PEST MANAGEMENT
Detailed information on integrated pest management
(IPM) for tomato production is available in the UC
IPM Pest Management Guidelines for Tomato, http://
www.ipm.ucdavis.edu/PMG/selectnewpest.toma-
toes.html. and in ANR Publication 3274, Integrated
Pest Management for Tomatoes, 4th edition. Cultural con-
trol methods such as mechanical cultivation, field san-
itation, good drainage, and irrigation management to
avoid excessively wet soils are important components
of IPM that help minimize the need for chemical con-
trols. Monitoring for and correctly identifying pests
are also key components of an effective IPM program.
Pesticides should always be used in compliance with
label instructions.
Weed Management
Control of annual and perennial weeds is important
for maximum crop production and harvest efficiency.
Hand-weeding can be a major expense in direct-
seeded fields if weeds are prevalent. Late-winter and
early-spring weeds can be controlled chemically or by
cultivation prior to planting. In direct-seeded fields
herbicides are often applied postemergence to seed-
ling tomatoes. Use of a preplant herbicide incorpo-
rated with a rotary tiller prior to transplanting is com-
mon. In fields with a history of nightshade (Solanum
nigrum and S. sarrachoides) infestation, a fumigant
can be banded along the seed line with a subsurface
spray blade prior to planting. Postemergent herbicide
sprays to control nightshades are also widely used.
Cultivation along the seed line precedes hand-thin-
ning and weeding in the seed line; no hand-weeding
is necessary in transplanted fields at this stage. Lay-
by herbicide application is the norm to control weeds
for the remainder of the season, regardless of planting
method. Additional hand-weeding may be required
to prevent escaped weeds from producing seed. Crop
rotation can reduce weed pressure.
Insect Management
The primary arthropod pests of tomato seedlings
are garden symphylans (Scutigerella immaculate), flea
beetles (Epitrix spp.), and cutworms (Peridroma and
Agrotis spp.). General foliage and fruit feeders are
tomato fruitworms (Helicoverpa zea), various army-
worms (Spodoptera spp.), russet mites (Aculops lyco-
persici), stink bugs (Euschistus conspersus, Thyanta pal-
lidovirens, Chlorochroa spp., and Nezara viridula), and
potato aphids (Macrosiphum euphorbiae). Pinworms
(Keiferia lycopersicella) are an occasional problem in
the southern San Joaquin Valley. Various insecticides
are used for control. A UC IPM monitoring program
is available for determining treatment thresholds for
fruitworm, armyworm, potato aphid, and consperse
stink bug control programs.
Nematode and Disease Management
Root knot nematodes (Meloidogyne spp.) have been
controlled under most circumstances by crop rota-
tion and use of resistant varieties. Phytophthora root
rot (Phytophthora parasitica and P. capsici) is a concern
throughout the season. Careful irrigation manage-
ment to avoid saturating soils for extended periods is
the most useful control practice.
The Mediterranean weather conditions of
California’s Central Valley limit disease problems.
In cool, rainy springs bacterial speck (Pseudomonas
syringae) and bacterial spot (Xanthomonas campestris)
can be problematic. Copper sprays are commonly
used. Bacterial speck–resistant varieties are widely
grown, but a new strain of the bacterium has recently
appeared that can cause disease even on resistant vari-
eties. Late blight (Phytophthora infestans) is a concern,
occurring in the late spring during rainy periods and in
the fall when wet weather returns. Protectant chemicals
may be used for control. In late-season fields protectant
fungicides are often applied to minimize fruit damage
from blackmold (Alternaria alternata).
3 • Processing Tomato Production in California
Fusarium wilt (Fusarium oxysporum) race 2 occurs
primarily in the Sacramento and northern San Joaquin
Valleys; race 3 is generally limited to the Sutter Basin
and Yolo County. Verticillium wilt (Verticillium dahliae)
race 2 is widespread but losses have not been devas-
tating. Corky root (Pyrenochaeta lycopersici) is common
throughout the Central Valley. The primary control
strategies of extending crop rotations and delaying
planting in fields with corky root history until soil is
warm are only partially effective. Fusarium root rot
(Fusarium solani) is becoming more prevalent.
Other Pests and Problems
A number of viruses can affect processing tomatoes,
including curly top, spotted wilt, and alfalfa mosaic.
The severity of loss to virus diseases varies from
year to year depending on factors such as weather,
populations of insect vectors (aphids, thrips, and leaf
hoppers primarily), and the presence of host plants
in the landscape. Significant economic losses may be
seen in individual fields or regions (particularly with
curly top and tomato spotted wilt), but in general
widespread losses are uncommon in California. The
whitefly-transmitted gemini virus tomato yellow leaf
curl (TYLCV) has recently been identified in tomato
fields in the Imperial Valley, but to date it has not
been found in the San Joaquin Valley.
HARVESTING AND HANDLING
All California processing tomatoes are mechanically
harvested. The once-over, destructive harvest is initi-
ated when at least 90 percent of fruit are ripe. In some
fields a fruit ripening agent is applied several weeks
before harvest to maximize the percentage of ripe fruit
and to promote earlier harvest. Some growers own or
lease self-propelled harvesters, although contract
harvesting by processors is common. Fruit are loaded
into tandem bulk trailers each holding approximately
12 tons and transported to a processing plant.
POSTHARVEST HANDLING
All bulk loads are graded at one of the fruit inspection
stations located throughout the production areas. The
Processing Tomato Advisory Board administers this
statewide program. Fruit color, soluble solids content,
pH, and defect levels (insect damage, mold, green
fruit, etc.) are evaluated. Tomatoes are then processed
into a wide variety of products. Some processing
plants directly manufacture finished consumer prod-
ucts, while others specialize in the production of bulk
paste or whole-peeled or diced fruit. These bulk items
are subsequently remanufactured into sauces, catsup,
and so on. Several small-scale processors produce
dried tomato products.
MARkETING
Processing tomatoes are grown under contract to spe-
cific processors. Growers are paid a contracted price
based on tonnage, quality, and date of delivery. Some
contracts also contain incentives for achieving high
fruit quality, particularly for soluble solids concentra-
tion. Processor requirements vary depending on the
desired end product. Some processors exclusively
produce products under their own proprietary labels,
while others specialize in producing bulk items for
remanufacture by other companies. Copacking agree-
ments, in which one processor manufactures prod-
ucts under specific guidelines for another processor,
are common. The production of organic processed
tomato products is increasing, although organics still
constitute a very small segment (less than 3%) of the
overall industry.
4 • Processing Tomato Production in California
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5 • Processing Tomato Production in California
Publication 7228
ISBN-13: 978-1-60107-570-3
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Division of Agriculture and Natural Resources
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