Broccoli Production in
california
MicHEllE lE StranGE, UCCE Farm Advisor, Tulare and Kings Counties;
MicHaEl d. caHn, StEVEn t. KoiKE, and ricHard f. SMitH,
UCCE Farm Advisors in Monterey, San Benito, and Santa Cruz Counties;
olEG dauGoViSH, UCCE Farm Advisor, Ventura County; StEVEn a.
fEnniMorE, UCCE Weed Specialist, U.S. Agricultural Research Station, Salinas;
Eric t. natWicK, UCCE Farm Advisor, Imperial County; SurEndra
K. dara, UCCE Farm Advisor, Santa Barbara and San Luis Obispo Counties;
EtafEraHu taKElE, UCCE Area Advisor Farm Management/Agricultural
Economics, Riverside County; and Marita i. cantWEll, UCCE Postharvest
Vegetable Specialist, University of California, Davis
Production arEaS and SEaSonS
Broccoli (Brassica oleracea L. var. italica) has been grown
in Europe for centuries, but it has only become an
important vegetable crop in the United States since
1925. California has four main broccoli production
areas: the southern desert valleys (Imperial and
Riverside Counties); the southern coast (Ventura, Santa
Barbara, and San Luis Obispo Counties); the central
coast (Monterey, San Benito, and Santa Cruz Counties);
and the Central Valley (Fresno, Stanislaus, and Tulare
Counties). Monterey County is the leading broccoli-
producing county in the state, with 40 percent of the
acreage and production. The south coast has about 30
percent of the acreage, while the desert valleys and the
Central Valley each account for about 15 percent.
In the Imperial Valley broccoli is planted from
early September through early December for harvest
from early December through mid-March. Broccoli is
grown year-round in the coastal valleys, with a slight
dip in December in both planting and harvest. In the
San Joaquin Valley broccoli planting begins in mid-
July and continues through December; however, most
planting ends in October. The major harvest is from
mid-October through December, with less acreage
being harvested through April.
Broccoli acrEaGE and ValuE
Year acreage
average yield
(tons/acre)
Gross
value/acre
2009 115,000 8.0 $6,073
2008 116,000 8.0 $5,718
2007 126,000 7.5 $5,313
2006 127,000 7.3 $4,885
2005 123,000 7.5 $4,226
Sources: California Agricultural Resource Directory 2006–2008 (Sacramento:
California Department of Food and Agriculture, 2008); and California Vegetable
Review 2009 (Vegetable Crops Summary, United States Department of
Agriculture, National Agricultural Statistic Service, vol. 31, no.1, 2010).
cliMatic rEquirEMEntS
Broccoli is a hardy, cool-season vegetable in the mus-
tard family. It is closely related to cauliflower and cab-
bage, and the cultural requirements for all are similar.
Broccoli seed will germinate and grow from 40° to
95°F (4° to 35°C), but optimum growth is obtained
when monthly air temperatures average from 60° to
65°F (16° to 18°C).
In commercial plantings under optimum condi-
tions, large leafy plants produce a compact flower
head on a tall, green, branching stalk. The center
flower head is from 3 to 8 inches (7.5 to 20 cm) in
diameter, and plants average 12 to 24 inches (30 to 60
cm) tall. Desirable broccoli has small uniform beads
(flower buds), good blue-green to green color, and
tight, dome-shaped heads that stand above the leaves
for ease of harvest. Hollow stems, watery head rot or
other diseases, brown or yellow beads, bracts within
heads, uneven bead size, and excessive branching are
undesirable.
cultiVarS
Growers of commercial broccoli in California use
hybrids of the Italian green type, also called green
sprouting broccoli or calabrese. Cultivars of this type
have been selected that take from 75 to 140 days to
grow from planting to marketable maturity. The vari-
eties differ in color and size of plant, size of head and
florets, and extent to which side shoots (small lateral
heads) develop below the terminal head. Proper cul-
tivar selection for each planting period and area is
critical to obtaining high yields and desirable head
quality.
Although broccoli grows best at cool tempera-
tures, substantial planting occurs when tempera-
tures are high in the hot interior and desert valleys
of California. However, growers select the planting
date so that the crop matures during the optimum
Vegetable
Production Series
vric.ucdavis.edu
UC Vegetable Research
& Information Center
University of California
Agriculture and Natural Resources
http://anrcatalog.ucdavis.edu • Publication 7211
http://vric.ucdavis.edu
http://anrcatalog.ucdavis.edu
temperature range; cold temperatures may also be
experienced, since these areas undergo cooler winters
than the coast. Seed company breeders, technical sup-
port and distributors, university researchers, and a
greenhouse/transplant industry help determine util-
ity of varieties through extensive trialing in grower
fields.
Principal broccoli varieties currently grown in
California are different for each growing region and
date of planting. Listed below in alphabetical order,
and not in order of predominance or time of planting,
are the popular varieties within each growing region.
In the central coast production area Concord,
Greenbelt, Heritage, Imperial, Legacy, Marathon,
Patriot, and Patron are commonly planted.
In the southern coast area Avenger, Green
Magic, and Heritage are common varieties. Belstar,
Marathon, and Patron are the most popular for
Ventura County.
In the southern desert Castle Dome, Coronado
Crown, Destiny, Emerald Crown, Expo, General,
Green Magic, Liberty, Sarasota, Tahoe, and XBC 5526
are commonly planted.
In the San Joaquin Valley cultivars include
Avenger, Expo, Green Magic, Legacy, Marathon,
Monte Carlo, and Tradition.
PlantinG
Broccoli can be direct seeded or transplanted. In the
southern desert valleys and the central coast almost
100 percent of the fields are direct seeded. In the
southern coast 75 percent of the fields are transplant-
ed. In the Central Valley approximately 70 percent
are direct seeded and 30 percent are transplanted.
Almost all broccoli, whether direct seeded or trans-
planted, is grown in double rows on raised beds 38
to 42 inches (95 to 105 cm) wide. Within-row spacing
is approximately 5 to 6 inches (12.5 to 15 cm) and
spacing between seed lines is 12 to 14 inches (30 to 35
cm). Broccoli is occasionally planted in single rows
on 30-inch (75-cm) beds with plant spacing at 5 to 6
inches (12.5 to 15 cm). A typical broccoli planting is
approximately 40,000 plants per acre (102,000 per ha).
When direct seeded, broccoli is planted with seeding
rates of 1 to 1.5 pounds of seed per acre (1.1 to 1.7 kg/
ha). Seeding depth ranges from 1⁄8 to 3⁄4 inch (3 to 19
mm), but most growers aim for 1⁄2 inch (12 mm).
SoilS
Broccoli grows best on well-drained soils and is
grown on a wide range of soil textures. Fields with
light soils are often designated for winter/spring
crops to minimize potential harvest delays caused by
rain. Broccoli is considered moderately salt sensitive,
having greater salt tolerance than some other crops
including melons, corn, lettuce, peppers, onions, and
carrots. Yield reductions have been measured at soil
salinity levels above 2.8 dS/m (ECe in mmhos/cm
at 25°C). Yield losses are approximately 9 percent for
each increase in soil salinity of 1 dS/m above this
threshold.
irriGation
Broccoli requires adequate soil moisture to maxi-
mize yield and quality, especially during flower head
formation. Overwatering can cause loose heads or
hollow stems to develop and can promote root dis-
eases. Broccoli is mostly irrigated with furrows and
overhead sprinklers. Many growers use sprinkler
irrigation through seed emergence or to set trans-
plants, then switch to furrow or drip irrigation for the
remainder of the crop. Most of the broccoli grown in
the Central Valley and Imperial County is irrigated by
furrow, and most of the acreage on the central coast is
irrigated with overhead sprinklers. After transplants
are established, irrigations with sprinklers are com-
monly at weekly intervals on the central coast during
the spring and summer. A small number of broccoli
acres on the central coast are produced using surface
drip irrigation. Drip is not commonly used during
the summer on the central coast because of difficul-
ties in achieving quality standards under high evapo-
transpiration rates. Some growers supplement drip
with furrow or sprinklers during the head develop-
ment phase. In Ventura County the acreage of broc-
coli grown on drip alone (including establishment)
is increasing. Approximately 2 to 3 acre-feet (2,480
to 3,700 cu. m) of water per acre is needed to grow a
sprinkler-irrigated broccoli crop in the Central Valley,
and 1.5 to 2.5 acre-feet (1,860 to 3,100 cu. m) is used
for broccoli production with sprinklers on the central
coast during the summer. Furrow irrigated crops in
Imperial County receive approximately 3 acre-feet
(3,700 cu. m.) of water per acre during the fall. Use
of drip irrigation can reduce water use by as much as
25 percent on soil types prone to runoff or on sandy-
textured soils that have limited water-holding capacity.
The amount and frequency of sprinkler or furrow
irrigation depends on soil type, weather conditions,
crop production area, and maturity. The combination
of soil moisture monitoring and weather-based irriga-
tion scheduling can be used to determine water needs
of broccoli. Water use is highest during the last month
of the crop, when vegetative growth is high. Soil
moisture tensions are typically targeted for less than
30 to 45 cbars (30 to 45 kPa) during this period. Soil
moisture is often allowed to reach moisture tensions
greater than 30 cbars between the first sidedressing
and flower head formation. Water extraction by the
broccoli crop can be estimated using reference evapo-
transpiration data adjusted with a crop coefficient that
is closely related to the percentage of ground covered
2 • Broccolli Production in California
by the canopy. At a maximum canopy cover of 95
percent, the crop coefficient is nearly 1.0. Crops estab-
lished with sprinklers should use a crop coefficient
between 0.3 and 0.7, depending on the frequency of
irrigation, until the canopy is greater than 30 percent
ground cover. The California Irrigation Management
Information System (CIMIS), coordinated by the
California Department of Water Resources, provides
daily estimates of reference evapotranspiration for
most production regions of California (see http://
www.cimis.water.ca.gov).
fErtilization
Broccoli is a very nutrient-demanding, cool sea-
son vegetable, and care must be given to provide
adequate nutrition to the crop. Soils on the central
and south coast regions can have elevated levels
of nitrate-nitrogen (NO3-N) and phosphate (P2O5),
which can cause elevated levels of these nutrients
in runoff. This makes it difficult for growers to com-
ply with water quality standards established by the
Regional Water Quality Control Board. As a result,
application of these nutrients needs to be carefully
managed.
Phosphorus (P) fertilization should be applied
based on soil test results for bicarbonate-extractable
phosphorus. Levels above 50 ppm are adequate for
broccoli growth; for soils below this level, especially
in the winter, preplant applications of 40 to 80 pounds
per acre (45 to 90 kg/ha) of phosphate are recom-
mended. The need for potassium (K) can also be
determined from soil tests; soils with greater than 150
ppm of ammonium acetate exchangeable potassium
have sufficient quantities of potassium for the crop.
Potassium fertilization presents no environmental
risk, and many growers routinely apply potassium
even in fields with high exchangeable soil potassium.
Although fertilizing to replace potassium removal
with the harvested crop (approximately 100 to 140
lb/ac [112 to 157 kg/ha]) is appropriate to maintain
soil fertility, fertilization rates above that level are eco-
nomically wasteful. Zinc fertilization is recommended
if DTPA-extractable soil level is less than 1.5 ppm.
Zinc fertilization is commonly practiced in the cen-
tral coast due to high soil phosphorus levels, which
reduce zinc uptake by plants.
Fall application of nitrogen (N) is not recommend-
ed due to the risk of NO3-N leaching beyond the root
zone by the winter rains. Small quantities of nitrogen,
20 to 30 pounds per acre (22 to 34 kg/ha), are applied
preplant or at planting. At the first sidedress, 50 to
80 pounds per acre (56 to 90 kg/ha) of nitrogen is
sidedressed into the beds. One or more additional
sidedressings are common, typically several weeks
apart. Seasonal nitrogen application to late-fall, win-
ter, or spring broccoli crops in the central coast region
ranges from 180 to 240 pounds per acre (202 to 270
kg/ha). Due to residual nitrogen from prior crops
and mineralization of nitrogen from soil organic mat-
ter, the nitrogen fertilization rates for broccoli grown
during the warm part of the year typically range from
160 to 200 pounds per acre (179 to 224 kg/ha). The
sidedress nitrogen requirement can be estimated by
pre-sidedress soil nitrate testing (PSNT). Soil nitrate
levels greater than 20 ppm in the top 12 inches (30
cm) are adequate for crop growth. The test can be
repeated later in the season to ensure continuing
nitrogen sufficiency. In drip-irrigated fields, nitro-
gen can be applied through the drip system as well.
Typically, drip systems are more efficient at managing
water and delivering nitrogen fertilizer, and therefore
fertilizer application rates are often 20 to 30 percent
lower than in furrow- or sprinkler-irrigated fields.
In the southern deserts and the Central Valley,
where soil test phosphorus is usually lower than on
the central coast, most growers apply preplant phos-
phate at 150 to 300 pounds per acre (168 to 336 kg/
ha). Ammonium phosphate fertilizers are broadcast
before listing or applied in bands during listing. The
remainder of the nitrogen is applied in one or two
sidedress applications of 50 to 80 pounds per acre (56
to 90 kg/ha).
intEGratEd PESt ManaGEMEnt
Integrated pest management (IPM) information is
continually being developed for weed, insect, and
disease problems in California broccoli. Cultural con-
trol methods such as mechanical cultivation, field
sanitation, good drainage, and irrigation manage-
ment to avoid excessively wet soils are important
components of IPM that help minimize chemical con-
trols. Pesticides should always be used in compliance
with label instructions. For more detailed information
about broccoli pest identification, biology, and man-
agement, consult ANR Publication 3442, Cole Crops:
UC IPM Pest Management Guidelines (available online
at the UC IPM Web site, http://www.ipm.ucdavis.
edu/PDF/PMG/pmgcolecrops.pdf).
Weed Management
Regional differences in weed problems are signifi-
cant. In the coastal areas winter and spring weeds
are favored by cool, moist conditions, and they pre-
dominate for most of the year. In the Imperial and
San Joaquin Valleys early crops compete with weeds
that germinate in warm to hot conditions from mid-
summer to late fall. Later fall and winter plantings
compete with annual winter weeds. During the cool
season, common problem weeds in all areas include
sowthistle (Sonchus oleraceus), burning nettle (Urtica
urens), chickweed (Stellaria media), common ground-
sel (Senecio vulgaris), little mallow (Malva parviflora),
3 • Broccolli Production in California
http://www.ipm.ucdavis.edu/PDF/PMG/pmgcolecrops.pdf
http://www.ipm.ucdavis.edu/PDF/PMG/pmgcolecrops.pdf
http://www.cimis.water.ca.gov
http://www.cimis.water.ca.gov
London rocket (Sisymbrium irio), prickly lettuce
(Lactuca serriola), and shepherd’s purse (Capsella bursa-
pastoris), and, during the warm season, they include
common lambsquarters (Chenopodium murale), night-
shades (Solanum spp.), purslane (Portulaca oleracea), and
nutsedge (Cyperus spp.).
Some growers manage weeds by stimulating weed
emergence with preplant irrigation. After weeds
emerge they are removed with shallow tillage, pro-
pane flaming, or herbicides.
Most conventionally produced fields are treated
with preplant and/or preemergence herbicides. A
month after planting, fields are mechanically cultivat-
ed and may be cultivated again about two weeks later
before the canopy closes. After cultivation a post-
emergence herbicide is often applied to control broad-
leaf weeds. Foliar applications of liquid ammonium
nitrate fertilizers also burn back broadleaf weeds.
Postemergence herbicides that control grasses are
registered for use in broccoli. Hand hoeing is done as
needed when the planting is 5 to 6 weeks old. Consult
your Farm Advisor for advice, as the registration sta-
tus of herbicides changes.
insect identification and Management
A wide variety of invertebrate pests can cause exten-
sive damage to broccoli. Cabbage and seedcorn mag-
gots (Delia sp.) burrow into broccoli roots and can be
difficult to manage. Flea beetles (Phyllotreta sp., Epitrix
cucumeris, and Systena blanda), wireworms (Elateridae
sp.) and cutworms (Agrostis sp. and Peridroma saucia)
are common seedling pests that may require control.
Cutworms tend to migrate into a crop from field mar-
gins. They feed at night, cutting seedlings at the soil
level.
The cabbage aphid (Brevicoryne brassicae) and the
turnip aphid (Hyadaphis erysimi) can contaminate
heads and must be controlled during head develop-
ment. The green peach aphid (Myzus persicae) can
build to damaging levels on leaves of young plants;
however, economic damage is rare on older plants
unless contamination of the harvested broccoli is at
issue. Aphids are attacked by generalist predators
and parasitic wasps, which can help suppress aphid
populations if insecticide use does not interfere with
their activity. It is important to scout for parasitized
aphids, or aphid “mummies,” which resemble dry,
rounded, tan to brown seeds. In cool, wet periods,
fungal diseases can also develop in aphid colonies.
Several species of worms such as loopers
(Trichoplusia ni and Autographa californica), beet army-
worm (Spodoptera exigua), and diamondback moth
(Plutella xylostella) are potential problems depending
on the time of year and weather conditions. These
caterpillars feed on foliage, and they can infest and
damage the broccoli head. All three types of caterpil-
lars are attacked by parasitic wasps in the egg and
larval stages. Pupal parasitism of diamondback moth
larvae and imported cabbageworm larvae can also
be significant. Predators and tachinid flies are signifi-
cant mortality agents of caterpillars attacking broc-
coli. Diseases, such as a nuclear polyhedrosis virus
that attacks cabbage looper, can also help suppress
caterpillars. Field scouts should look for evidence of
natural enemy activity when monitoring aphids and
caterpillars in broccoli. Worms should be managed
by using selective insecticides to avoid making other
insect problems more severe. Rotation of insecticide
classes is essential for insecticide-resistance manage-
ment. Concerns of resistance to new-generation pes-
ticides are present whenever one chemical is heavily
relied upon as a control measure.
The silverleaf whitefly (Bemisia argentifolii) can
cause significant damage to fields in the southern
desert valleys if not controlled, but only isolated inci-
dences have been observed elsewhere in the state.
Early-season plantings in the southern desert and
San Joaquin Valley are more likely to be attacked by
seedling pests and worms than are late-season plant-
ings. Broccoli planted in the coastal valleys must be
monitored on a year-round basis to determine if pop-
ulation pressures warrant an insecticide application.
General UC recommendations
