Greenhouse-Grown Bell Pepper Production
The Tomato Magazine
August 2006
Bell pepper growers in Florida,
and perhaps other areas of the country, have a viable alternative to growing
them in the field. During the 2002-2003 growing
season, 17,800 acres of bell peppers were planted and mostly green bell pepper
fruits (mature but unripe stage of fruit development) were harvested from
these field crops. Colored bell pepper fruits (ripe) attract market values
that are three to five times greater than green fruits, but high fruit quality
and yield of colored fruits are difficult to obtain in open field environments.
High-quality colored bell peppers can, however, be produced year round and
especially during the high-priced off seasons, in protected environments
such as high passively ventilated greenhouses. Fruits can be harvested with
red, orange, or yellow color depending on the pepper cultivar used. Indeed,
essentially all of the high-quality and high-value colored bell peppers imported
to the United States are grown in greenhouses. In Florida, a small number
of growers already produce high-quality colored fruits in an area of about
45 acres.
During the past six years, University of Florida scientists at the Protected
Agriculture Project, lead by Daniel J. Cantliffe, have been examining the
production of greenhouse-grown peppers in Florida (http://www.hos.ufl.edu/protectedag/).
Scientists Elio Jovicich, Daniel J. Cantliffe, John J. VanSickle, Lance S.
Osborne, Nicole L. Shaw, Peter J. Stoffella, Steven A. Sargent, and Margaret
L. Smither-Kopperl examined the production of greenhouse-grown peppers in
Florida.
“The initial impetus for this research was to explore which greenhouse
and management practices for pepper would work best in Florida,” says
Jovicich. “We
wanted to adapt what other countries were using and found that greenhouse
roofs needed to be high to provide ventilation and allow cooling, shade systems
and supplemental fuel heating were needed, and fertigation could be done
in containerized plants filled with low-cost soilless media.”
In the U. S., the consumption of high-quality red, orange, and yellow bell
peppers
(Capsicum annuum) has been increasing dramatically the past decade. To satisfy
consumer demand, Mexico, The Netherlands, Canada, Israel and Spain export
high-quality greenhouse-grown peppers into the United States. In Florida,
high market prices, consumer demand, and a suitable environment for growing
colored peppers under protected agriculture have encouraged greenhouse growers
to consider the economic viability of this crop.
The impending ban on methyl bromide, along with greater demand for high-quality
colored peppers, may give growers a reason to consider growing peppers in
greenhouses. Other pressures include urban sprawl and subsequent high prices
for arable land. For the past five years, pepper ranked first in production
area in Florida’s total greenhouse area dedicated to vegetable crops
(followed by tomato, cucumber, and lettuce).
Jovicich, VanSickle, Cantliffe and Stoffella simulated a full production
of greenhouse-grown peppers under a passively ventilated structure in Florida
using management practices necessary to successfully grow peppers and turn
a profit. The estimates indicate that production of greenhouse-grown peppers
could represent a viable vegetable production alternative for Florida growers
and possibly for growers in other regions of the United States.
A greenhouse production system of peppers greatly differs from the traditional
field pepper cultivation system where plants are grown on polyethylene-mulched
beds and with drip irrigation. In greenhouses, high fruit yield and quality
are produced in a small area during an extended growing season. Moreover,
soil sterilization is not needed, and water and nutrients that drain from
the bottom of the plant containers can be recycled. The enclosed environment
also makes the use of biological control practices for pest management more
effective than in open fields, actually allowing the production of fruits
that are pesticide-free.
Marketable fruit yields will vary with greenhouse location, growing season,
plant density, trellis system, cultivar, irrigation, and fertilizer management.
Current marketable yields of 1.6 to 3.0 lb. per square foot and potential
yields of 4 lb. per square foot can be obtained in Florida in passively ventilated
greenhouses with low use of heating fuel. “However, because of the
higher costs involved with greenhouse growing systems compared to growing
in the open field, greenhouse growers have to manage their crops to maximize
fruit yield and quality while minimizing production costs per unit of greenhouse
floor area,” says Jovicich.
Greenhouse Structures
In Florida, there is currently a trend towards using high-roof, passively
ventilated greenhouse structures (13 foot or more to the roof gutter) for
protected vegetable production.
The greenhouses are covered with polyethylene, which is replaced every three
to four years. The side walls and roof vents can be covered with insect screens
to restrict the entrance of pest insects and to keep beneficial insects,
such as bumblebees, within the greenhouse.
“
These high-roof greenhouse designs are less expensive and more suited for
use in regions with subtropical and tropical climates than structures covered
with glass or polycarbonate,” says Jovicich. “Costs of passively
ventilated greenhouses can range as much as 80 percent less per square foot
than the types of greenhouses that seek maximum climate control.” Greenhouses
with passive ventilation and heating provide a level of climate control that
enables plants to survive and produce at economically sufficient yields.
Cultivars
Sweet pepper cultivars most commonly used in greenhouse production are hybrids
that have bell-shaped or blocky-type fruits with red, orange, or yellow color
when mature.
“Cultivars should be selected for a grower’s ability
to market them, as well as pest and disease resistance or tolerance, low
susceptibility to fruit disorders, and yield and quality performance,” says
Jovicich. Some of the commonly used cultivars are Parker, Triple 4, Cubico,
and Lorca for red, Kelvin for yellow, and Neibla and Emily for orange fruits.
However, new pepper cultivars for greenhouse production are introduced by
seed companies every year.
In a pepper cultivar trial conducted in a passively ventilated greenhouse
in Gainesville, Florida, the total marketable yield was acceptable for 23
cultivars tested when grown and harvested during the winter months in north
central Florida, according to a study by Shaw and Cantliffe in 2002. The
red and yellow cultivars produced fruit yields of 1.8 to 2.2 lb. per square
foot and the orange cultivars had yields of 1.4 to 2 lb. per square foot.
When comparing cultivars for those with the highest yield and fruit quality
characteristics with low amounts of culls or other disorders, the best red
cultivars in the study were Lorca, Torkal, Triple 4, and Zambra; yellow cultivars
were Pekin, Kelvin, Neibla, Bossanova, and Taranto; and orange cultivars
were Paramo, Lion, and Boogie.
Growing Seasons
The most common greenhouse pepper production season extends from mid-July
or early August to May. Long crops of up to 300 days are transplanted during
the second or third week of July with a first harvest around the middle of
October, ending in late May. Depending on fruit prices and on the quantity
and quality of the fruits harvested, production may be extended until June.
High temperatures and humidity during July and August adversely affect production
but are good for young plant growth. With some cultivars, percentages of
unmarketable fruits increase during the late spring mainly due to a higher
incidence of blossom-end rot and fruit cracking. Fruit set can also be low
during the summer due to high rates of flower abortion under high temperatures.
Air ventilation and shade materials for 30 percent shade help reduce high
temperatures during the late spring, summer, and early fall. Currently, water
misting is being evaluated as a cooling system for plants transplanted in
the summer. Cold weather during winter can also adversely affect the set
of marketable fruits due to poor pollination and delay maturation and earliness
in production. “In central and northern Florida, optimum daytime temperatures
required for pepper production can easily be achieved in winter while optimum
night temperatures cannot, and therefore, heating during the night is necessary
to increase fruit yield and improve fruit quality,” says Jovicich.
Soilless Culture Systems
Greenhouse pepper crops in Florida are grown in soilless culture. Methyl
bromide is not needed since problems with soil-borne diseases and insect
and nematode pests are avoided. The plants are grown in containers filled
with soilless media, such as perlite, pine bark, or peat mixes. The media
can be reused for two or three crops if disease contamination does not occur.
The containers used are nursery pots (three and four gallons) with one plant
per pot. Another planting scheme uses flat polyethylene bags that are three
foot long (five gallons) with three to four plants per bag. The plant containers
can be aligned in single or double rows, one next to the other, and can lead
to plant population densities of 0.27 to 0.36 plants per square foot.
In local trials with greenhouse-grown peppers, fruit yields from plants grown
in three-gallon pots or five-gallon flat bags have been similar. Also, similar
marketable fruit yields were harvested from plants grown in various substrates,
such as perlite, pine bark or peat-perlite mixes. “Pine bark, milled
and sieved to particle sizes smaller than one square inch, have shown to
be a promising medium in Florida because of its low cost, availability, lack
of phytotoxicity and excellence as a plant production media,” says
Jovicich.
Irrigation and Fertilization
Pepper plants in soilless culture are fertigated frequently with a complete
nutrient solution. Nutrient solution concentrations are similar to those
used for tomatoes grown in soilless culture. The concentrations of most of
the nutrients required by pepper plants in larger quantities are increased
with plant growth. For example, in the irrigation solution used with soilless
culture, the concentration of nutrients in parts per million (ppm) can be
N:70, P:50, K:119, Ca:110, Mg:40, and S:55, starting when transplanting the
seedlings.
In plants at full production, the nutrient concentration levels can reach
N:160, P:50, K:200, Ca:190, Mg:48, and S:65 ppm, respectively.
At the time of transplanting, seedlings can be irrigated about 10 times a
day and deliver about 1.3 fluid ounces per irrigation event. As plants grow
and season temperatures rise, irrigation frequency and volume per irrigation
event can be increased up to 40 times a day and deliver about 2.5 fluid ounces
per irrigation event.
Systems for recycling the fertigation solution are available and provide
a more sustainable use of water and nutrients. “With these ‘closed’ irrigation
systems, the solution that drains from the pots is sanitized and then the
pH and EC are corrected to meet the plant needs. Subsequently, the nutrient
solution can be recycled on the same pepper crop,” says Jovicich.
Transplanting, Pruning, and Training
Transplanting of plants is also a bit different in greenhouse production.
Frequent irrigation and high levels of salt deposits near the cotyledonary
node level can promote localized epidermal injuries on a swollen stem base
and fungal infection can lead to basal stem rots and sudden plant wilts.
To avoid injuries to the plant stem below the cotyledonary leaves, seedlings
should be transplanted into the soilless culture substrate to the depth of
the first leaf node. To reduce creating a humid environment at the base of
the stem, irrigation emitters that are placed near the seedling stems at
transplanting can be gradually moved back two to three inches from the base
of the pepper plants over a three-week period.
Greenhouse pepper cultivars generally have an indeterminate pattern of growth.
Because the plants can grow up to six foot tall during a growing season of
250 days, they need to be supported vertically. Pepper plants can be trellised
to the Dutch “V” system or to the “Spanish” system.
The “V” system consists of forming a plant with two main stems
by removing one of the two shoots developed on each node and leaving one
or more adjacent leaves per node. The pairs of stems are kept vertically
by the use of hanging twines that wind around the stems as they grow.
In the “Spanish” trellis system, the plant canopy is allowed
to grow without pruning. The plants are vertically supported by a structure
of poles and horizontal twines extended on both sides of the plant rows.
Labor requirement for the “Spanish” system is reduced minimally
by 75 percent of the labor used compared with the “V” trellis
system. In a study where the two trellis systems were compared, the percentage
of fruits with blossom-end rot at the end of the spring was lower in the
non-pruned plants.
Pollination
While pepper plants are self-pollinated, the use of bumblebees inside the
greenhouse help to ensure the set of high-quality fruits, especially during
the cool season when pollen viability is lower. “Although one bumblebee
hive (containing 60 bees) per 16,000 square feet might seem costly to the
grower, pollination done by workers would be less efficient and much more
expensive,” says Jovicich. “The hive should be placed under a
shade in summer and in the sun in winter and isolated from ants. The hives
should contain a supplement food for the bees during periods of low abundance
of flowers because over-visited flowers may lead to fruits with cork-like
spots at the blossom-end.”
Harvesting and Packing to Maintain Postharvest Fruit Quality
Throughout the harvest season, pepper fruits ripen in flushes or waves of
production. Under warm environments, fruits can be picked once or twice a
week at close to full color. Nonmarketable fruits should be removed from
the plants as soon as they are observed. Clipped peduncles keep a better
appearance during shipping and handling and cause fewer injuries to adjacent
peppers.
Marketable fruits are graded by diameter, and fruits with greater size bring
higher prices. Fruit grades can follow the USDA standards for field-grown
peppers or classifications based on diameter ranges similar to greenhouse
peppers imported from Holland (extra-large, diameter more than 3.3 inches;
large, 3 to 3.2 inches; medium, 2.5 to 2.9 inches; and small, 2.2 to 2.3
inches).
Peppers should not be submerged in water during the transfer to the packing
line since water can easily infiltrate the hollow pod and cause postharvest
decay. The use of overhead spray with clean water and brush rollers works
well for washing.
Pepper fruit respiration can be delayed by quickly cooling the product to
the lowest safe temperature of 48 to 50° F and 90 to 95 percent relative
humidity, resulting in a postharvest life of two to three weeks. Rapid cooling
of harvested sweet peppers is essential in reducing marketing losses. Forced-air
cooling is the preferred method.
Pre-cooling within a few hours of harvest and storage in a high relative
humidity will minimize weight loss and shrivel symptoms, and maintain firmness.
Waxing provides some surface lubrication, which reduces chafing in transit.
Water loss can also be limited by packing cooled peppers into cartons with
moisture-retentive liners or into perforated polyethylene bags.
Pests and Diseases
Pests are reduced but not eliminated in screened greenhouse structures. Transplants
must be free of pests and weeds must not be present inside the greenhouse. “The
major arthropod pests observed in greenhouse peppers in Florida are broad
mite (Polyphagotarsonemus latus), two-spotted mite (Tetranychus urticaae),
western flower thrips (Frankliniella occidentalis), melon thrips (Thrips
palmi), green peach aphid (Myzus persicae), melon or cotton aphid (Aphis
gossypii), silverleaf or sweet potato whitefly (Bemisia agentifolii), pepper
weevil (Anthonomus eugenii), fungus gnats (Bradysia spp.), and several lepidopterous
pests.”
Fungal diseases that may be present are powdery mildew (Leveillula taurica)
and Fusarium (Fusarium oxysporum and F. solani).
Insecticides are available to control insect and mite pests. However, many
chemicals negatively affect bumblebees, beneficial organisms, and the pepper
plant itself. Some products, such as soaps, oils, and sulfur, are often phytotoxic
to pepper plants in the greenhouse.
Biological control practices used in other regions and crop systems are being
evaluated by researchers in the Protected Agriculture Project at the University
of Florida and at the Mid-Florida Research and Education Center.
Compared to the use of pesticides, with biological control, insects do not
develop the resistance that they do to certain insecticides. Also, restricted
reentry period to the greenhouse due to the use of insecticides are eliminated,
the environment for workers is safer, and harvest products can be labeled “pesticide
free,” which may bring higher prices and/or increase consumer demand.
The use of biological controls will require that the crop is scouted frequently
to determine presence and to estimate population densities of crop damaging
pests and their natural enemies.
The production of greenhouse-grown peppers represents an alternative crop
in Florida, and ongoing research by the Protected Agriculture Project continues
on greenhouse-grown peppers on production systems, fruit quality, cultivars,
nutrient and water management, integrated pest and disease management, postharvest,
and marketing.
© 2006 Columbia Publishing
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