FLORICULTURAL PRODUCTION AND MANAGEMENT Part I: Background and Introduction Neil Anderson Horticulture is the fastest growing segment of The diverse number of crops produced requires each agriculture within the United States. An array of employee in the distribution channel, including floral products provides market diversity for the breeder and producer companies, distributors, floriculture industry. These include flowering potted propagators, pre-finish and finish growers, and plants, foliage plants, cut flowers, cut foliage, annual retailers, to be trained in maximizing crop growth bedding and garden plants, and herbaceous biennials potential and quality. Knowledgeable and perennials. In 2003, the wholesale value of U.S. implementation of optimal post-harvest care and floricultural crops was $5.07 billion for 11,913 handling treatments ensure maximum product shelf growers with sales greater than $10,000 and 929 life for the retailer and maximum performance for the million ft2 in production. For growers with sales consumer. Keeping up-to-date with the latest greater than $100,000, the crop total was $4.76 production techniques ensures sales of top-quality billion. While this crop category is in the top five plants which will maximize earning potential. "crops" surveyed by the U.S. Department of Agriculture, it contains multiple commodity groups Knowledgeable manipulation of the growing with hundreds of plant species. The largest environment is required to maximize floriculture floriculture commodity is bedding and garden plants production and profit, as well as to continue the at $2.42 billion (51%), followed by potted flowering tradition of grower excellence in the Midwest. Refer plants at $829 million (17.4%), potted foliage at $623 to the Plant Propagation, Container Production, Pest million (13.1%), herbaceous perennials at $620 Management, Insect Management, Disease million (13.0%), cut flowers at $425 million (8.9%), Management and Water Management in this manual propagative material at $351 million (7.4%), and cut for additional information. foliage or greens at $109 million (2.3%). This industry enhances the lives of every citizen by providing color and interest to indoor and outdoor environments. Flower power and convenience are two important features of floricultural crops, particularly annual bedding plants. In Minnesota, annual, perennial, groundcover, herb, vegetable, and potted flowering plant production is valued at a wholesale value of nearly $86 million and it continues to grow! More than 250 Minnesota commercial companies produce these crops in approximately 13 million ft2 of greenhouse space consisting of glass, fiberglass, rigid plastic, and film plastic greenhouses, plus shade houses. In the near future, the industry estimates that the sales of annuals and perennials will increase by 30%. Part of this anticipated growth will arise from the many new crops entering the market each year, as well as the extended summer sales opportunity for bedding plants beyond the traditional Mother's Day to Memorial Day sales period. 43.1-1 1106 FLORICULTURAL PRODUCTION AND MANAGEMENT Part II: Greenhouse Production and Management Terry Ferris Flower Induction, Initiation and Development in between 35o F and 48o F. For example, perennials Floriculture Crops such as Asclepias tuberosa and Astilbe need twelve Growers always strive to have healthy, vigorous weeks of cold to break dormancy and flower. foliage on greenhouse crops, cut flowers and most Hydrangeas and Azaleas require six weeks of cold to bedding plants. Growers also need to ensure the develop flowers. Tulips and Narcissus initiate timely presence of flowers on flowering crops. flowers during the warm summer, however, they However, before a plant can flower, the plant must need a cold treatment to promote rooting, shoot reach a physiological readiness, and then, either reach elongation and subsequent floral development. plant maturity or receive an environmental stimulus to induce the plant to flower. Once induced to Light Intensity and/or Accumulated Light – Light flower, flower parts are initiated at the tip of the intensity controls floral induction and initiation in meristem. The initiated parts then develop by some species. African Violets need a minimum of enlarging and taking on qualitative changes such as 500 foot-candles for flowering. Zonal Geraniums color and fragrance. Floral induction and initiation will not flower when light intensity is too low. are controlled by one set of conditions while floral development may be controlled by the same or by Daylength – Plants measure the length of the light different set of conditions. Several different floral and dark periods of the day through phytochrome control mechanisms exist in the plant world. pigment which absorbs red and far-red light. This Growers need to know what controls flowering in phenomenon is referred to as Photoperiodism. order to schedule the production of a crop. Growers Darkness also affects phytochrome in a similar should consult supplier brochures, industry manner that far-red light does. It is actually the colleagues, or the scientific literature to identify length of the darkness that is most important in specific mechanisms. Floral control mechanisms or controlling the phytochrome response. The common plant conditions are described as follows: photoperiodic response groups include the following: Age of Plant or Number of leaves – In some plant 1. Obligate Long-day Plants species, the age of the plant, or more specifically, the Obligate Long-day plants flower only when the number of leaves formed, controls when the length of the day is greater than some critical induction and initiation of flowering will occur. For minimum time, which is usually 12 hours. example, Cyclamen start initiating flowers after Examples include Wave Petunias, Lobelia and seven or eight leaves are formed. Easter Lilies start Gazania. Many of these plants bloom naturally in flowering after 86 to 93 leaves have formed and Corn the summer. will flower after 22 leaves have formed. 2. Obligate Short-day Plants Specific Temperatures – For many plants, a specific Obligate Short-day plants flower only when the temperature range is required for floral induction and length of day is shorter than some critical initiation. For example, Cineraria initiates buds after maximum which is usually 12 hours. Many of four weeks at 45-55o F and Calceolarias need six these bloom naturally in the fall and include weeks at 50o F to flower. Poinsettia, Chrysanthemum and Kalanchoe. Vernalization – Some floricultural crops require an 3. Day-neutral Plants exposure to cool temperatures for extended periods of Day-neutral plants are plants whose floral time to either initiate flower buds or to promote floral induction and initiation are not controlled by day development. In nature, this temperature is generally length. Examples include Roses, Impatiens, between 32o F and 50o F. Growers use a temperature Nicotiana and Centrathus. 43.2-1 0510 4. Facultative Long-day Plants exchange, the side walls may be constructed of Facultative Long-day plants flower faster or have inflatable poly tubes with an inflation fan connected more flowers under long-days. Flowering is not to a thermostat that will inflate the tubes, or deflate specifically controlled by photoperiod, but is and collapse the tubes to let in fresh outside air influenced by it. Examples include Petunias, depending upon the temperature. Pansy, Dianthus and Sunflowers. Purlins – Purlins run horizontally from rafter to rafter 5. Facultative Short-day Plants and provide additional support. These may be Facultative Short-day plants flower faster or have especially important in high wind and heavy snow more flowers under short-days. Flowering is not load areas. specifically controlled by photoperiod, but is influenced by it. Examples include Zinnia, Ridge – The Ridge refers to the peak of the Cosmos and Rieger Begonias. greenhouse where the two sides of the roof meet. Round roofs would not have a distinct Ridge. Growers need to be aware of conditions that control floral induction and initiation as well as those that Eave – The Eave of a greenhouse is where the influence floral development. The two processes sidewall meets the roof. When the Eave of one may require different conditions. greenhouse is common with an adjacent greenhouse, the Eave area is referred to as the Gutter. Greenhouse Structures Greenhouses are built with a slight drop from one end The short growing season in the upper mid-west wall to the opposite end wall to allow gravity to limits year-round outdoor production of many facilitate the runoff of water down the Gutters. This floriculture crops. Therefore, greenhouse production water can be collected in underground storage tanks is an essential part of many commercial floricultural and used for irrigation or on the cooling pads. operations. The greenhouse structure that a grower selects will be influenced by the initial capital Span – The Span of a greenhouse is the width, or available and the cultural requirements of the crops to distance from one Eave to the next Eave, both being be grown. Structural components of greenhouses are under one Ridge. described below and pictured in Figure l. Rafters – Rafters provide vertical support and can be part of a triangular truss or they can be arched as in quonset-type greenhouses. Spacing of the rafters influences the strength of the structure. Rafters are generally spaced on two- to four-foot centers. Very wide greenhouses