Commercial Greenhouse Production
Scientific Name: Saintpaulia ionantha
Common Name: African Violet
Dr. J. Raymond Kessler, Jr.
History and Use
The African Violet, Saintpaulia ionantha, is among the most popular of house plants with wholesale sales in 1995 exceeding 25 million dollars. This popularity is due to its ability to thrive under conditions commonly found in most homes, and its usefulness as a specimen plant, center piece, or feature in dish gardens.
Since its introduction into the United States in 1894, hundreds of African Violet cultivars have been developed that provide a wide range of flower colors, foliage types, and plant sizes. Though many Americans purchase African Violets as an impulse item, there are dedicated enthusiasts who grow, breed, and show them.
African Violets were originally discovered in 1892 in two separate locations of northeast Tanga in Eastern Africa by Baron Walter von Saint Paul, then governor of German East Africa. Saint Paul sent either plants or seed to his father in Germany where they quickly became popular in European Horticultural circles. Herman Wendlan, a prominent botanist at the Royal Botanical Gardens in Herrenhausen Germany, gave the genus name Saintpaulia in honor of its discoverer, and the two species, S. ionantha and S. confusa, became parents to most of the cultivators available today.
Most commercial growers of African Violets in this country do so on a modest scale. These growers usually obtain established transplants from a wholesale propagator for either year-round production or, more often, to meet seasonal demand. However, there are a number of large scale operations that propagate and produce upward of one million plants a year. The primary marketing holidays for African Violets are Saint Valentine's Day, Easter, and Mother's Day.
Cultivars available for greenhouse production have been selected for consistent production timing, vigorous performance in the different climatic regions of the country, trueness to type, uniform flowering, and market acceptance. From a sales point of view, an important consideration is to provide customers with a wide variety of flower colors and cultivar selection to maintain interest. In general, cultivars are placed into flower color categories; red, blue, purple, lavender, pink, white, or bicolor. Within these color categories, 2-10 cultivars of each color may be on the production list but only one or two will be finished each week and then rotated with the next set.
Growers must consider the adaptability of cultivars to their production conditions. At some time each year, new cultivars should be ordered and evaluated for possible introduction into production based on performance under existing conditions. Recently, new introductions of different African Violet forms including miniatures and trailers have gained the attention of producers and customers. Three of the main U.S. breeder/propagators are Holtcamp greenhouses who offer the 'Optimara', 'Ballet', and 'Rhapsody' series, Arnold Fisher Greenhouses, and Nortex Nursery Industries.
African Violets are usually incompatible with other greenhouse crops because of their environmental requirements. Therefore, the grower should consider planning to use a separate greenhouse or controlled section for production. This facility should have excellent capacity for temperature, humidity, and light control.
AfricanViolets have an above average night temperature requirement. Night temperature should be 68-70F for the most rapid vegetative growth with a 75-80F day temperature. An average daily temperature of 77F provides the highest rate of leaf unfolding. When the day temperature exceeds 85F, plants often flower prematurely and grow poorly. For this reason, fan and pad cooling systems are almost mandatory in warmer areas of the country. Plant growth slows at a night temperature of 65F, and almost stops at or below 60F. Propagation areas are often maintained 2-4F warmer at night than production areas.
Bench surface heating or under-bench heating pipes are effective for increasing the growth of 