BACKGROUND
When fresh cut flowers receive optimal care from harvest to consumer, they have
better quality and last longer. This requires attention to details, e.g.,
selecting long-lasting varieties, maintaining good sanitation practices, and
providing retail customers with flower food. Our research has focused on ways to
make flowers last longer. We have developed a simple checklist to ensure
long-lasting flowers.
VARIETIES
Vase life begins with flower variety. Some varieties will last longer than
others even when production and postharvest conditions are optimal. Our tests of
60 varieties of Roses found vase life to range from 3 to 21 days. Breeders,
growers, wholesalers and retailers can and should test variety vase life on a
regular basis to ensure long-lasting varieties are dominating the marketplace.
HARVEST
Longest lasting flowers must be harvested at the correct stage of development.
Roses, Gladiolus, and Lilies should be cut when buds are starting to open.
Chrysanthemums and Carnations should be harvested when buds are half open.
HYDRATION
Cut flowers need to be hydrated at each level of distribution: grower,
wholesaler, and retailer. Hydration solutions contain a buffer to lower pH,
biocides to kill microorganisms on stems and in solutions, and a wetting agent
to accelerate water uptake. When using hydration solutions, the most important
considerations are: (1) to use freshly made solutions and (2) to use clean,
sanitized water and buckets.
If flowers have been hydrated in solutions with high microbial populations, the
microbes travel with flowers and can ultimately reduce vase life and quality.
High microbial levels (greater than 100,000 colonies forming units per ml of
solution) clog the water transport systems of stems.
Based on our research, best results occur when stems are hydrated for 1-3 hours
at room temperature in clean buckets filled with freshly mixed solutions.
Hydration times must be increased when hydrating stems in the cooler.
For retailers, recutting stems underwater is effective only if the water is
clean and free of bacteria. Cutting stems dry does not diminish vase life. When
cutting stems dry, plunge them immediately into solutions.
PACKING
Reduce moisture on leaves, stems, or petals prior to packing. Dry stems reduce
free moisture in shipping boxes, which can help to reduce the incidence of
Botrytis. Growers can place hydrated flowers in an empty bucket or container in
a cooler (relative humidity 75%) for 2-3 hours.
Growers should pack flowers in a cooler maintained at 36-38 F. Moving flowers
from a cooler to a room temperature packing room and back into a cooler causes
condensation to form on stems in the shipping box, which can promote Botrytis.
Chlorine dioxide-releasing paper placed in flower boxes has been designed to
reduce the incidence of Botrytis during storage and when transport times are one
week or less.
SPECIALIZED TREATMENTS
Some cut flowers are sensitive to ethylene, which accelerates senescence and
causes flowers, buds, or leaves to drop, wilt, or discolor, and prevents flower
buds from opening. Anti-ethylene compounds, such as EthylBloc (1-MCP) or
slow-release EthylBloc sachets protect flowers from ethylene injury. These
products are applied to flowers in gas form before, during of after shipping.
Cut flowers can also be protected from ethylene by hydrating stems in silver-
thiosulfate (STS) products, such as Chrysal AVB.
Some flowers experience leaf yellowing, which can be eliminated by identifying
tolerant varieties or using specialized treatments. Alstroemeria, Oriental and
Asiatic Lilies, and Calla lilies experience little or no leaf yellowing when
stems are hydrated using commercial anti-leaf yellow products, such as Chrysal
BVB and Floralife PAL. Improved OASIS Floral Foam with Floralife Technology
reduces leaf yellowing of Alstroe-meria and Chrysanthemums without any prior
specialized treatments.
SANITATION
Buckets, tools, cutters, tables, vases, working areas, and coolers must be
cleaned and sanitized. Use freshly mixed solutions at least daily. Mix fresh
solutions between different batches and types of flowers. Clean buckets with an
anti-bacterial product before adding floral solutions. Use a professional floral
bucket cleaner or bleach, kitchen sanitizer, or chlorine dioxide.
TEMPERATURE
Temperature control is vital to provide consumers with long-lasting flowers.
Ideal air storage temperature for most cut flowers is 33F to 35F. Tropical
flowers, such as Anthurium, Orchids, and Ginger require 50F to 55F.
Low temperatures reduce plant metabolism and ethylene sensitivity. Cold air also
slows multiplication of microbes in storage solutions.
At the retail level, vase life for some flowers, such as Roses, decreases 30-50%
if flowers are displayed at or above 50F. Flowers will last longer if stems are
kept cold in the retail shop during display.
FLOWER FOOD
Retailers should ALWAYS provide flower food to customers and review mixing
instructions with them. Using properly mixed flower food consistently increases
vase life and improves flower opening. Always use specialized foods designed for
specific floral species.
CONCLUSIONS
Long-lasting flowers can be marketed to consumers. The guidelines below will
enhance cut flower vase life:
- Choose long lasting varieties
- Harvest flowers at the correct stage of development * Hydrate flowers in
clean, microbe-free water with a freshly made solution - Dry flowers before packing
- Treat appropriate flowers with anti-ethylene and anti-leaf yellowing
compounds - Sanitize all buckets, tools, cutters, tables, vases, working areas and
coolers - Store non-tropical flowers at 33-35F
- Always provide flower food for customers
IMPACT TO THE INDUSTRY
Providing long-lasting flowers is the most direct way to encourage customers to
buy more cut flowers. By vigorously following simple steps, growers,
wholesalers, and retailers can provide long-lasting cut flowers.
Source:
Dept. of Environmental Horticulture, University of Florida, Gainesville