Announcements

Job offersmore »

Tweeting Growers

Last commentsmore »

Top 5 - yesterday

Top 5 - last week

Top 5 - last month

Exchange ratesmore »




The importance of keeping flowers cold

In the floral industry, there’s increasing recognition of the importance of cold temperatures — and providing cold temperatures for every flower from the point of harvest to the point of sale. (One notable exception to this rule: tropical flowers.) And, just for clarity, "cold" means 34 F to 36 F.

by Terril A. Nell, Ph.D., AAF



Why is the cold so important? Low temperatures extend vase life and optimize the performance of cut flowers. Moreover, cold temperatures are easily managed by adjusting the thermostat and monitoring the temperature in the cooler. Sounds simple enough, right? In theory, yes, but in reality, and for various reasons, it is not unusual to observe flower shop coolers at 42 F to 45 F. Those higher temperatures reduce flower life, which can lead to disappointed customers.



Why does cold temperature have such a big influence on the performance of flowers? Three factors help explain the science.

Respiration
Flowers use stored sugar and starch to maintain the structure and function of cells in the flowers, leaves and stems. Sugars provide the energy for flowers to open and to extend flower life. Without sugar, cells starve, blooms fail to open, and death occurs prematurely. Cold storage temperatures lower the respiration rate and allow sugars to be conserved. See the graph for an illustration of how rapidly consumption of sugars and starch increase as temperatures rise. Flower foods provide sugar to supplement the stored sugars used by the flower during storage, shipping and handling.

Ethylene
Ethylene kills flowers. At cold storage and shipping temperatures, however, flowers are less sensitive to atmospheric ethylene and do not produce as much ethylene internally. In fact, flowers are 1,000 times more sensitive to ethylene at 65 F than they are at 35 F.

Diseases and microbial activity
The spread of diseases such as botrytis on flower petals and growth of microbes in bucket and vase solutions are reduced significantly at cold temperatures. Botrytis spores grow and destroy flowers rapidly at warm temperatures. These spores are not killed by cold temperatures, but the spread of the disease is much slower. Microbes block the flow of water up the stem. Microbes present in bucket and vase solutions grow much faster in warmer water.

Realizing how cold temperatures affect respiration, ethylene and disease makes it possible to extend the life of flowers. But temperature is only one of the key factors in flower life. Equal priority needs to be placed on the other factors affecting the absorption of water, particularly scrupulous sanitation, ethylene management and the use of properly prepared hydration and flower food solutions.

Terril A. Nell, Ph.D., AAF, is professor emeritus at the University of Florida, a consultant to the floral industry and the research coordinator for the American Floral Endowment. This article was originally printed in SAF's August issue of Floral Management. This is the fifth of a five-part series. To view the rest of this series, visit: safnow.org/moreonline

For more information
American Floral Endowment
T: +1 (703) 838-5211
www.endowment.org

Publication date: 8/9/2018

 


 

Other news in this sector:

8/9/2018 Are Kenyan flowers actually more sustainable?
7/20/2018 UK: Saffie's rose named after youngest victim of Manchester terror attack
7/20/2018 "There will always be a market for quality"
7/19/2018 NL: Gladiolus also suffering from hot summer
7/11/2018 NL: Getting people excited about fragrant roses
6/28/2018 Flower exports earned Kenya $420 million in four months
6/28/2018 Rhein-Maas supports Concours Bouquets d’Aujourd’hui at Salon du Végétal
6/20/2018 Arend Roses launched large-flowered coral rose
6/19/2018 Video: Discover where flowers begin
6/18/2018 Australia: Flower growers give country-of-origin label laws a spray
6/13/2018 Rose reveals its secrets to researchers of Wageningen
6/13/2018 Russian florists busy preparing for the wedding season
6/12/2018 UK: Lily is in the July Flower Agenda
6/5/2018 Royal Flowers opens sales office in the Netherlands
5/29/2018 NL: 10,000+ roses decorate 'Shop for a Week'
5/29/2018 UK: Rose grower picks Chelsea favourites
5/18/2018 UK: Peony is on the Flower Agenda in June
5/16/2018 Australia: 42,000 sunflowers grown to raise awareness for stillbirth
5/8/2018 Scadoxus is looking for grower
5/8/2018 Israel: Phlox season in full swing

 

Leave a comment: (max. 500 characters)

  1. All comments which are not related to the article contents will be removed.
  2. All comments with non-related commercial content, will be removed.
  3. All comments with offensive language, will be removed.




  Display email address

  new code