Authors: Ritu Jain and Prabhat Kumar
Division of Floriculture and Landscaping, ICAR- IARI, New Delhi 110012
Flowers are highly perishable commodities and there are enormous losses in value of cut flower all along the market channel and are estimated to be 30-40 per cent of farm value. Flowers needs gentle handling as they continue to live after harvest at the expense of reserve food. The nature and extent of postharvest damage is typical for each crop or cultivar. The post harvest losses become important especially when dealing with the export of fresh flowers to distant and foreign market. Therefore, patient, soft and expert handling of flowers is of utmost importance after harvest.
After harvesting the following factors play an important role in determining the life of the flowers
Temperature: At high temperature, the rate of respiration increases and stored reserve food of flower depletes and postharvest life is shortened, therefore it is desirable to store and transport the flowers at low temperature.
Light: Some of the flowers like alstroemaria, lilies and chrysanthemum shows leaf yellowing during storage, therefore, a provision of light should be there in cold stores or transport vehicles.
Relative humidity: Cut flowers contain higher amount of water in their tissues and transpiration rate is higher under low RH conditions and flowers will loose turgidity. Therefore maintain 70-80 per cent relative humidity for storage and transport.
Ethylene: Most of the flowers are sensitive to ethylene and keep on producing ethylene after harvest. Therefore, store flowers away from fruits and vegetables and use anti ethylene scrubbers like KMnO4 or anti ethylene agents like 1 MCP.
Methods to prolong the vase life of cut flowers
Conditioning/hardening: Conditioning is done immediately after harvest, storage or transport as flowers restore the turgor. Use de-mineralized water supplemented with germicides and acidified with citric acid along with wetting agents like tween 20 @ 0.01-0.10% can be used for this purpose.
Precooling: The flowers should be kept under shade immediately after harvest and in order to remove field heat, precooling is must as it lowers down the metabolic activities of the flowers. Precooling can be done with ice cold water, cold water or forced air.
Impregnation: It is generally practice in crops like Gerbera, Carnation, Chrysanthemum and Gladiolus. Loading of flowers with high concentration of metal salts (silver nitrate or nickel chloride of cobalt chloride) for a short period of time is known as impregnation. It is helpful in reducing the attack of microbes and synthesis of ethylene.
Pulsing: Pulsing is beneficial treatment for flowers destined for long storage period or long distance transportation. For this treat the flowers with high concentration of sucrose and germicide for a short period of time to improve the vase life and flower opening.
Bud opening: To promote the opening of immature buds in crops like chrysanthemums, rose, carnation, gladiolus, and snapdragon use bud opening solutions containing germicides, sucrose and hormonal solution.
Cold storage: After pre-cooling and pulsing the flowers can be stored at low temperature i.e. in cold store to regulate the flower market or to avoid the glut in the market. Controlled atmospheric (CA) modified atmospheric (MA) or hypobaric (LP) storage method can be used to enhance the vase life of flower.
Holding: After storage and transport the flowers should be kept in a solution containing sucrose, germicide ethylene inhibitor and growth regulator. The flowers can be kept in holding solution either at wholesaler, retailer or consumer level.
Few tips to increase vaselife
- Harvest the flowers at optimum stage.
- Aviod crushing or bruising of stem.
- Immediately after harvest place flowers in clean buckets and containing water.
- The buckets should be cleaned with germicides to avoid any microbial attack.
- Keep the flowers in shade immediately after harvest.
- Sort and grade the flowers, remove any diseased or injured or pest infested flower.
- Pack the flowers according to standards and grades and precool them.
- Avoid storage and transport of flowers with fruits and vegetables.
- Give a slanting cuts to woody stemmed flowers before keeping in preservative solutions.
About Author / Additional Info:
Working as scientist at ICAR- Indian Agricultural Research Institute, New Delhi