Peppers (greenhouse)

Bell peppers are among the many common household varieties of capsicum annuum, an annual shrub belonging to the nightshade family. Colors of bell peppers might be green, orange, yellow, purple, brown, or red depending on maturity. Sugar content in peppers increases as they ripen, hence red peppers are considered the sweetest and green more bitter. Botanically speaking, the pepper is a fruit because it has seeds.

As demand for fresh bell peppers continues to climb, U.S. supply has been increasingly augmented by both domestic and international greenhouse production. Though the majority of peppers are imported from Canada and Mexico, as well as some from the Netherlands, Spain, Israel, and the Dominican Republic, U.S. production is rapidly expanding with new greenhouses popping up across the country.

Even within a protected environment, pepper yields will vary by location, season, plant density, trellis system, cultivar, irrigation, and fertilizer management.

References: Agricultural Marketing Resource Center, Foodland Ontario, PennState Extension, Purdue University, University of Florida.


The most common greenhouse peppers are sweet bell varieties—green, orange, yellow, and red. Cultivars are generally hybrids selected for marketability, pest and disease resistance or tolerance, and overall yield and quality. Among the popular varieties are Parker, Triple 4, Cubico, and Lorca for red; Kelvin for yellow; and Neibla and Emily for orange. New cultivars for greenhouse production are regularly introduced by seed companies.

Cultivars can be distinctly different, enough to require varying growing environments for maximum yield. Some greenhouse growers are also experimenting with field-grown varieties.

References: Agriculture & Agri-Food Canada, Cornell University, Foodland Ontario, Purdue University, UC Davis Postharvest Technology Center, University of Florida, USDA.


Peppers are generally grown in a soil-less culture. Nursery pots (3 and 4 gallon) with one plant per pot or flat polyethylene bags (5 gallon) with 3 to 4 plants per bag are used. Containers are filled with media such as perlite, pine bark, peat mixes, or sawdust.

At the time of transplanting, seedlings can be irrigated up to 10 times per day, increased watering during higher light levels and longer days. Night irrigation may be considered during warmer weather.

Ventilation provides a more uniform climate, helps distribute heat, and can’t dehumidify the greenhouse environment. Temperature is regulated, depending on the stage of development and cultivar grown. Generally, temperatures should not exceed 70 to 79°F, with an optimum temperature range of 70 to 73°F.

Plants generally grow up to 6 feet tall during a season, and require vertical support. Peppers are often trellised with the “V” system or in a double row trellis via the “Spanish” system. In the Spanish method, the plant is allowed to grow without pruning.

When pruning is required, plants are generally managed with two main stems per plant and pruned every two weeks. It is important when pruning to ensure the main stem or growing point remains intact.

References: Agriculture and Agri-Food Canada, Alberta Agriculture and Rural Development, Foodland Ontario, USDA National Agricultural Library, University of Florida.

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