Postharvest handling of cut flowers 

Advanced Course onPostharvest Technology

November 2003, Mauritius

Dr. Ron Porat

Dept. of Postharvest Science of Fresh Produce

ARO, The Volcani Center, Bet Dagan, Israel

Among horticultural crops, cut flowers have perhaps the highest commercial value but are most perishable: they loose a lot of water, have high respiration rates, and are susceptible to physical damage.

Factors affecting postharvest longevity and quality of cut flowers

• Maturity stage• Carbohydrate supply• Temperature• Water loss• Ethylene• Mechanical damage• Diseases

Maturity stageCut flowers are usually picked when the buds are

starting to open. (rose, gladiolus).

In some cases, the flowers must be picked open (chrysantemum, carnation).

Carbohydrate supply

The reserves of starch and carbohydrates in the leaves

and stems are usually not enough to support energy

for proper bud opening and maintenance.

Therefore, cut flowers are often pulsed for up to 24 h

with a solution containing sugars (from 2 to 20%

sucrose).

Control 5% Sucrose

Liatris

TemperatureFlowers have high respiration rates, which increases

logarithmically with increasing temperatures.

Cooling slows respiration and delays senescence.

The optimal storage temperatures for most cut flowers are between 0-2ºC.

Tropical flowers, like anthurium and several orchids, that are sensitive to low temperatures should be kept at 10-13ºC.

Forced-air cooling of cut flowers

Water loss

Flowers have a large surface area and, therefore, they loose water rapidly.

Flowers should be stored at low temperatures and at a relative humidity of 95% to reduce water loss and wilting.

The main causes for problems in water uptake are:Air embolism: occurs when bubbles of air are drawn

into the stems at the time of cutting.Air bubbles can be removed by re-cutting the stem.Bacterial plugging: Growth of fungi and bacteria can

plug the water transpiration system. To avoid this, holding solutions should be acidic (pH 3.5) and contain germicides.

EthyleneMany flowers perish rapidly in response to ethylene.

Carnations, orchids, etc. – ethylene induces senescence

Snapdragon, delphinium, etc. - ethylene induces abscission

It is important to avoid pollution with ethylene, to remove ethylene from storage rooms by ventilation, and to treat the flowers with ethylene action inhibitors (STS, 1-MCP).

Mechanical damageBruising and injuries are undesirable from an aesthetic

point of view, but also provide pathogen invasion sites.

The cut flowers must be wrapped carefully and be protected by polyethylene sleeves, shredded paper, etc.

DiseasesDecay, especially gray mold caused by Botrytis cinerea,

provides a major cause for postharvest losses.

The cut flowers should be kept at low temperatures without water condensation.

Carmen

Control TOG-MJ-1

A.Red Charm

Control TOG-MJ-1

B.Frisco

Control TOG-MJ-1

C.

Effect of combined treatment of pulsing and spraying with TOG-MJ-1 on appearance of various cut rose cultivars

following artificial infection with Botrytis(Spraying with 0.6% TOG-MJ-1 / pulsing with 0.4% TOG-MJ-1)

7 days in vase life

Pink Tango

Control

D.

TOG-MJ-1Control TOG-MJ-1

E. TamaraSun Beam

TOG-MJ-1

F.

Control

Harvest

Grading

Bunching and sleeving

Chemical pulse treatments

Packing

Cooling

Dry or wet storage

Transportation

Marketing

Postharvest handling of cut flowers

Postharvest vase solutions

Vase solutions typically contain:• Low concentrations of sugar (0.5-2%)• A biocide [usually hydroxyquinoline (HQC) or TOG]• Citric acid (300 ppm) to keep a low pH.

Handling requirements of some representative cut flowers

Anthurium* Storage at 10-12C.

* Prevent mechanical damage by wrapping with plastic sleeves and fill-packing boxes with shredded paper.

Roses• Pulse treatments with fungicides (vinclozolin,

iprodione, copper) against Botrytis cinerea. • Storage at low temperature (0-2C) without water

condensation.• Usually, not treated with sugar or ethylene inhibitors.• Add bleach to the vase solution.

Gerbera• Are long lasting (till 20 days). • Add bleach to vase solution• Trim stems every few days

Lilium• Pulse treatment with GA and STS. • Add bleach to vase solution

GladiolusPulse with high concentrations of sugar (10%), STS

and a fungicide.

Thank you for your attention!