While most cut flowers are currently imported from out-of-state producers, Oklahoma growers can substantially contribute to and profit from the production and marketing of cut flowers. Greenhouse or garden centers could diversify their operations with cut flowers, depending upon proper care of the flowers and establishment of a market. Since Oklahoma is centrally located in the U.S. and has two major airports, increased production of cut flowers could be warranted. Therefore, establishing care and handling guidelines is critical to the success of cut flower production in Oklahoma. Below is basic information which may be useful to growers, wholesalers, retailers, and ultimately the consumers.

Since water quality and growing, harvesting, and storing conditions vary considerably, it is important to first test any changes in procedures on a small scale. Whether a firm is growing or importing cut flowers, periodic tests of the vase life of the flowers should be conducted to assure that vase life is adequate. Flowers may look acceptable, but may not last as long as possible.

Harvesting the Flowers

Before a single flower is harvested, a few items should be prepared first. All buckets and utensils should be cleaned and sanitized. Cutting tools need to be sharp; dull tools will macerate stems and reduce water uptake. Plants should be healthy and vigorous. Flowers harvested from poor quality plants will generally have a shorter vase life than those harvested from high quality plants. Finally, the vase life of a
species can vary greatly, depending on the cultivar; cultivar selection criteria should include both production capability
and vase life protection.
Flowers should be harvested at the proper stage of development for maximum vase life. The optimum stage varies with the species grown and the time of the year. Some species may be harvested at a less mature stage during the summer, when warmer temperatures may induce rapid development. Morning harvest is often advantageous over afternoon harvests, because the temperature is lowest during the morning, plant water content is high, and the rest of the day is available for packing and flower distribution.

Temperature

As storage temperatures rise, respiration and water loss increases and wilting ensues. Therefore, rapid cooling is imperative to remove field heat and greatly improve quality and vase life of cut flowers. Cool flowers as soon as possible and maintain a temperature range of 32 to 35oF (0-2oC). Just a few additional degrees warmth can significantly decrease vase life. Flowers stored at 41oF, for example, may deteriorate up to four times faster than those stored at 32oF. However, to increase water uptake initially, place the stems in warm water and allow the water to reach ambient temperature gradually. Once packed, flowers are difficult to adequately cool. Try to pack the flowers in a cold room and, when possible, force cool air through perforations in the storage boxes.

Relative Humidity

The ratio of water vapor pressure in the air to vapor pressure in saturated air at a given temperature is known as relative humidity (RH). Relative humidity can be determined by comparison of the wet bulb and dry bulb temperatures on a psychrometric chart. Devices for measuring these properties are available commercially at a low cost. Proper RH plays a significant role in increasing longevity of cut flowers. Strive for a RH over 90%, but less than 100%. If water droplets start forming on the flowers and foliage, a common fungus known
as botrytis may attack.

Nutrition

Starch and sugars (carbohydrates) stored in cut flowers are responsible for flower opening and longevity. Carbohydrate levels are highest when cut flowers are grown under proper nutrition, temperatures, light levels, and water supply. Quality and longevity of cut flowers are improved by placing stems in sugar (sucrose) water. Place the flowers in a cool room but in warm water (110oF/43oC). Sugar added to
holding solutions will enhance flower size and color throughout the vase life of the flowers. Many excellent commercial floral preservatives are available on the market today, some of which come in powder form to be mixed with water.
Automated application systems can be purchased to mix solutions more easily, and premixed are available with a liquid silver treatment (see ethylene section) as well.

Tags: flowers humidity, flowers temperature, flowers growing, cut flowers, handling flowers

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