Why Do Cut Flowers Wither Earlier Than Expected?

  • offcial website of Beijing Expo 2019  2017-Sep-15 13:28:12

1.Insufficient water supply

Cut flowers wither earlier than expected because they lack sufficient water supply. To keep them alive and fresh longer, we must find ways to make the flowers better absorb water. Water supply can be insufficient for the following reasons:

(1)Air enters ducts and forms bubbles which blocks water absorption;

(2)Succulent plants have their ducts blocked by surplus juice which blocks water absorption; or

(3)The cuts are infected with bacteria and result in decay which destroys the water absorption function.

To keep cut flowers fresh, we must maintain a high level of water concentration and saturation. Otherwise, the flowers will wither and die. The flowers lose their source of water supply once they are cut. With transpiration continuing to function, the water absorption of the cut flowers is affected so that their water balance is lost. Secretion, bacteria or bubbles can all result in blocked ducts. Contaminated preservative solutions for cut flowers in vase displays can often cause leaves and petals to wither or bend. That is the case for cool lilac, rose, chrysanthemum and African daisy, which have ducts that are easily blocked. Roses are vulnerable to the largest number of conditions, which are caused by insufficient water supply. The other major reason is that the roses are harvested too early.

2.High temperatures

High temperatures result in a higher frequency of breaths and greater loss of energy. High temperatures lead to a higher speed of development, which results in early withering of cut flowers, thus shortening the lifespan of cut flowers. Lower temperatures can delay the aging process of cut flowers. At the same time, low temperature hinders the generation of a large quantity of ethylene. At 0-5 degrees Celsius, cut flowers are not affected by ethylene. Therefore, cut flowers should be stored and transported under low temperatures whenever possible. Ordinary tropical and sub-tropical flowers need to be stored at 5-15 degrees Celsius while temperate flowers should be stored at 0-4 degrees Celsius. If fresh tap water is used, no heating is needed for water at room temperature. Though tap water is an easy solution, tap water alone is not enough to keep cut flowers fresh. Preservatives are the best choice.

(1)Iced water. The ducts in the stems might be blocked by bubbles in the water, which results in hindered water absorption and shortens the lifespan of cut flowers in vase displays. Iced water can dissolve such bubbles and make the ducts unimpeded in water absorption. Conclusion: Iced water can be used for cut flowers in vase displays.

(2)Room temperature tap water. Water at room temperature is easily available and convenient to use. Tap water at room temperature is best used in combination with preservatives. It can be used directly from the tap. No heating or cooling is needed. Conclusion: Tap water at room temperature is the best and most readily available choice.

(3)Moderately heated tap water. Some people believe that moderately heated tap water can help dissolve preservatives. If the tap water is not heated, preservatives will fall to the bottom of the vase. Conclusion: The thinking behind this concept is flawed.

(4)Cold boiled water. Water which cools down after being boiled has a reduced level of oxygen or air content. It is better for keeping cut flowers fresh because it does not easily result in blocked ducts. Conclusion: This is the right idea. However, preservatives for cut flowers can solve the problem of air content in water. It is therefore not necessary to bother with cold boiled water.

3.The generation of ethylene – physiological conditions thrown off balance

Ethylene is extremely closely related to the freshness of cut flowers. Ethylene is generated by cut flowers as they decay and in turn promotes further decay. The final result is withering and deterioration. Various hormones are automatically generated when flowers are cut. A great quantity of ethylene occurs during this process.

4.Insufficiency of nutrients – nutrients thrown off balance

The content of carbohydrates, a very important building block in cut flowers, determines the quantity of the flowers. After they are cut, the flowers depend on the nutrients stored in their stem for their metabolism. Cut flowers wither because respiratory substrates are insufficient and the withering speed is dictated by the content of nutrients in the stem. Additionally, metabolism generates hazardous substances, such as ammonia, polyphenols and ethylene. Sufficient nutrients ensure the best growing conditions for flower shapes, colors and fragrance. The stiffness of the stem is also subject to the supply of nutrients.

(1)Buds do not blossom. Flowers age early and blossom too early or don’t blossom at all.

(2)Cut flowers don’t blossom fully. Flowers don’t bloom to normal shape and size. Examples include baby's-breath, chrysanthemum and eustoma grandiflorum.

(3)Color fading. The color of flower petals is not as bright or strong as it was when they were first purchased.

(4)Fragrance thins out or disappears. Example: roses.

5.The quality of water

Low pH values help maintain water balance inside the plant itself. Reproduction of cells is repressed when the pH value is 4 or less, which depresses enzyme activity and alleviates the blocking of the ducts. This can increase the life of some cut flowers. Generally speaking, hard water or alkaline water work against cut flowers while fresh water and moderately acidic water work for cut flowers. Ideally, water should be used only after treatment. Tap water should be left for some time before use. The best pH values are from 3.5 to 4.5 and this can depress the reproduction of microorganisms and increase the absorption of the stem.