Ornamental Pepper Production Tips

June 11, 2002 - 12:51

Ornamental peppers are an excellent niche plant for summer, fall and winter holiday production. The production tips listed here may help you fine-tune your growing program to produce a higher-quality crop.

There are over 30 cultivars of ornamental peppers available.
Many of the older cultivars like ‘Filus Blue’ or ‘Bolivian
Rainbow’ are tall-growing and make excellent background plants in the
landscape. Plant breeders at the USDA in Beltsville, Md., have been working
with ornamental peppers since 1991 and have released a number of new cultivars.
This includes a number of compact cultivars that are excellent for container or
border plants. Some of the newer cultivars even have fruits that are not hot,
like ‘Medusa’ from Pan American Seed Co. Floricultureinfo.com
contains additional information about 17 cultivars of ornamental peppers that
were trialed at North Carolina State University. Some of the outstanding
cultivars from the trials included: ‘Jigsaw’,
‘Starburst’, ‘Masquerade’, ‘Pretty Purple’,
‘Treasures Red’, ‘Marbles’ and Medusa.

Growing perfect peppers

Scheduling. Plants can be sold “green” 8-10 weeks after
sowing or when the peppers have colored after 15-20 weeks. Crop time is usually
2-3 weeks shorter during summer production.

Seeding. Germination takes from 7-12 days at 70-75° F.
Seeds can be sown in plug trays and transplanted into the final container
within 15-20 days after sowing. Avoid letting plugs become root-bound in the
plug tray before transplanting, as restriction of root growth can stunt and
stall the crop.

Containers. The most common container used for finishing is a 5-inch
pot with one plant per pot. With all the possible variations in leaf color,
fruit shape and growth habit, the uses of ornamental peppers are only limited
by your imagination. Larger containers also make a colorful display with three
plants per 6-inch pot or mum pan or a larger specimen plant in a patio
container. Some growers also produce 1801 cell packs for spring sales. This
works especially well for the purple or variegated foliage cultivars, Á
which consumers can easily differentiate from the peppers used in the vegetable
garden.

Root Substrate (Medium). style='font-weight:normal;font-style:normal'> An ideal mix should allow for
rapid root development while maintaining good water-holding capacity. Mixes
that stay too moist may cause shoot growth to become weak and chlorotic, due to
the lack of oxygen in the substrate, and increase the chances for root rot to occur.
Peat-based mixes with large perlite or pine bark are good choices to provide
ample water retention and drainage.

Irrigation. Ornamental peppers are not very forgiving of water stress,
and repeated wilting can lead to lower leaf loss, fruit drop and a poor-quality
crop. Drip or subirrigation should be used to prevent the foliage from staying
too wet, which can promote Botrytis. If hand-irrigating, consider morning
irrigations to allow the foliage to dry during the day to avoid the occurrence
of Botrytis or root rot.

Nutrition. Ornamental peppers are moderate feeders. High levels of
phosphorus (P) and ammoniacal-nitrogen (NH4-N) (> 40 percent of total N)
and/or urea in a fertilizer mix should be avoided to prevent excessive stem
elongation. Ornamental peppers will become soft and leggy with excessive
fertilizer.

Water quality will affect which fertilizers to use. If your
irrigation water is alkaline, use a 20-10-20 or similar acidic formulation to
aid in pH management. If your irrigation water has low alkalinity, consider
using a 13-2-13 calcium-magnesium or similar basic formulation to aid in pH
management. Weekly rotation of an acid and basic fertilizer can be a useful
tool to ensure proper pH balance for the crop.

Once the cotyledons protrude from the germination substrate,
Á the first fertilization to the plug tray can be made. For the seedling
stage, fertilize at a rate of 50-75 ppm of nitrogen with a constant liquid
feed. Once plants are established, the recommended fertilization rates are
between 150 and 200 ppm nitrogen (constant liquid feed).

Plants have a moderately high requirement for calcium and
magnesium. If these two elements are not supplied in irrigation water, then
they need to be supplied through fertilization. The use of calcium nitrate or
the calcium-magnesium fertilizer formulas will provide adequate calcium. To
supply magnesium, monthly applications of epsom salts (MgSO4·7H20)
should be made at the rate of 1-2 lbs. per 100 gallons of water.

The root substrate pH and electrical conductivity (EC)
should be monitored on a weekly basis because of the potential of salt
accumulation and/or the development of high or low pH values. The pH range
should be between 5.8 and 6.2. Low pH will cause the lower leaves to develop
dark purple spots. EC levels should be maintained between 0.5-1.0 mS/cm for the
2:1 extraction method; 1.0-2.0 mS/cm for the saturated paste extraction method;
or 1.5-2.8 mS/cm for the PourThru extraction method. Excessively high fertility
rates can be detrimental to fruit set.

Temperature. Once established, temperatures should be around 75° F
during the day and 65° F at night. Avoid temperatures below 45° F, or
chilling injury can occur. Temperatures above 85° F during fruit set (and
magnified if nutrient levels are excessive) can result in crop delay because of
flower/fruit abscission.

Fine-tuning

Height Control and Pinching style='font-weight:normal;font-style:normal'>. Tall cultivars of ornamental
peppers will require pinching or plant growth regulators (PGRs) to maintain compact
growth. Taller cultivars can be soft-pinched 6-8 weeks after sowing. Pinching
results in bushier plants but may increase the crop time by two weeks. Pinching
of compact cultivars like Medusa is not recommended because it results in a
clumpy appearance.

There are a number of PGRs that are suitable for use on
ornamental peppers. Sumagic foliar sprays can be applied around 8-10 weeks
after sowing at the rate of 10-15 ppm for taller cultivars or 5-10 ppm for
medium-sized cultivars.

Bonzi also controls the height of ornamental peppers.
Research at NC State University found that a Bonzi foliar spray at 20 ppm was
comparable to Sumagic at 10 ppm on the Pretty Purple variety. Bonzi also had
the advantage of not reducing the number of fruits on each plant, while the use
of Sumagic resulted in a 36-percent decrease in fruit number.

B-Nine at 2,500 ppm can also be used for medium-sized
cultivars. Compact cultivars may not require any PGRs. The above rates were
determined in the Southeastern United States for a crop maturing during late
summer. Rates should be adjusted for other locations and times of year.

Earlier research at the University of Georgia found that
Florel at 150-300 ppm promotes earlier red and orange fruit coloration of
ornamental peppers, although Florel is not registered for ornamental peppers.
Our trials at NC State University found that foliar sprays of 150 ppm applied
3-6 weeks after flowering hastened red fruit coloration by 2-3 weeks. A
sufficient number of fruits must be near mature size prior to applying Florel.
Florel applications will cause all flower buds and some of the small fruit to
drop; rates higher than 300 ppm can even result in large fruit drop.

NOTE: PGRs can only be used on ornamental peppers not
intended for consumption.

Pepper pests, pestilence and postproduction

Major Insect Pests. A number of insect pests can attack ornamental
peppers. The major ones include aphids, spider mites and thrips. Aphids can be
controlled with foliar sprays of Endeavor, Horticultural Oil, Insecticidal
Soap, Marathon, Orthene or Thiodan. Akari, Avid, Floramite, Hexygon, Floramite,
Ovation, Pylon or Sanmite are all potential controls for spider mites. Thrips
will feed on the immature leaves, causing leaf distortion, and the fruit, which
results in a whitish appearance. Control thrips with Avid, Conserve or Mesurol.

Major Diseases. The most common diseases of ornamental peppers are
Botrytis, impatiens necrotic spot virus (INSV) and Pythium. Botrytis, or gray
mold, commonly occurs during wet conditions accompanied by poor airflow. Drip,
subirrigation or hand irrigation in the morning, along with good air movement
will help avoid this problem. Daconil Ultrex, Decree, Dithane or Kocide will
help control Botrytis.

INSV appears as a dark, greasy stem lesion or a dark
ringspot on the leaves . The disease is spread by western flower thrips, and
once the plant is infected, it needs to be discarded. Western flower thrips
control is required to control this disease.

Pythium root rot can occur if the soil is kept too moist.
Managing the irrigations so that the substrate is not excessively wet will help
avoid problems. Possible controls for pythium include Aliette, Subdue Maxx and
Terramaster.

NOTE: The pesticides listed above can only be used for
ornamental peppers not intended for consumption.

Post-Production Care. Temperatures can be decreased to 60-65° F
nights and 65-70° F days to help prolong fruit quality. Low-light
conditions can result in fruit drop, and exposure to ethylene during shipping
should be avoided.

About The Author

Brian E. Whipker is assistant professor, James L. Gibson and Todd J. Cavins are graduate research assistants, and Ingram McCall is a research technician in floriculture at North Carolina State University, Raleigh, N.C. Colleen Warfield is assistant professor in ornamentals pathology at NCSU, and Raymond Cloyd is assistant professor in ornamentals entomology at the University of Illinois, Champaign-Urbana, Ill. They can be reached by phone at (919) 515-5374 or E-mail at brian_whipker@ncsu.edu.

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