Increasing Flowering Potted Plant Longevity Progress Report –June 1999
A COMPREHENSIVE PROGRAM TO INCREASE THE LONGEVITY OF FLOWERING
POTTED PLANTS
Terril A. Nell, Ria T. Leonard, Jim Barrett and Dave Clark
Environmental Horticulture Department
University of Florida
1. Industry Needs and Project Objectives:
The overall objective of this project is to determine the effects of
production, transport, retail and consumer conditions on longevity and quality
of flowering potted plants. In the last year, we have worked to expand the crops
evaluated and to identify the critical factors leading to increased longevity
and quality of a wide range of flowering potted plants.
2. Summary of work conducted since inception
With the crops evaluated and treatments imposed on these crops, we have
evaluated the longevity of over 25 floral crops in this program, including
longevity of leading varieties, effects of fertilizer concentration, type and
termination/continuation, transport duration and temperature and retail/interior
conditions. Specific treatments vary with crop being evaluated.
In the past year, we have evaluated the longevity of hydrangea, heimalis
begonia and African violet. A brief summary of the results for each crop is
provided below:
- Hydrangea
- Four varieties were evaluated. Longevity was greatest with
Vulcan Blue (42 days) and shortest with Leuchtfeur (13.5 days). Fertilizer rate
and termination/continuation was evaluated on Leuchtfeur using rates of 125,
200, 275, 350 and 425 ppm N at every watering. Longevity was reduced from 19.5
days at 125 ppm to 14.5 days at 425 ppm. Fertilizer termination at first flower
color did not affect longevity at fertilizer rates of 200 and 300 ppm. The
amount of bract color affected longevity, with 50% color development at time of
boxing having the shortest longevity. These results may be due to disease
problems during transport simulation. Transport for periods longer than 6 days
resulted in a 30 - 50% reduction of longevity at all temperatures (35, 45, 55
and 65 F). Interior longevity was greatest when plants were held at temperatures
of 70 f and 100 ft-c. and shortest at 75 F and 100 ft-c of light.
- Two cultivars, Sonata and Takora Yellow, were grown in
our greenhouses. Longevity was excellent with all treatments, exceeding 50 days
in most treatments. Longevity was greatest, 66 days for Sonata and 60 days for
Takora Yellow, when fertilized with 75 ppm at every watering compared to
52 and 47 days respectively, with 300 ppm. Fertilizer termination
increased longevity 2 days at 75 ppm and 5 days at 300 ppm. Stage of
development (number of open flowers) when marketed had no effect on
longevity. Longevity was greatest when plants were transported at 45 or 55
F compared to 65 F. Longevity was similar in plants stored for 3, 6 and 9
days.
African Violet - Production conditions were not evaluated on
african violets. Two varieties were obtained from a commercial grower at
marketing stage and placed into our interior rooms at either 65, 70 or75 F
with 50 or 100 ft-c. of light, 12 hours daily. Plants remained in these
conditions for 62 days. The number of open flowers was counted daily. The
results were surprising! Within 14 days on ‘Wyoming’ and 35 days on
‘Michigan’, plants held at 70 F and 100 ft-c. had more flowers than
the other treatments. By day 62, ‘Wyoming’ plants in these conditions
had 3-4 times more flowers (18) than the other light/temperature
treatments. Treatment differences were not as great on ‘Michigan’
plants.
3. Next steps and future for project and anticipated industry
benefit(s).
We will continue to evaluate longevity of different flowering potted
plants in order to provide all segments of the industry with information
on practices to maximize quality and longevity for the consumer. In
addition, we will be building ethylene gas chambers so we can evaluate
these practices under conditions characteristic of storage, transport and
retail display so that the effects of ethylene will be more
understandable. Then, we can provide information on differences between
ethylene sensitivity and generation and procedures to reduce the effects.
The results of this research will be published in trade magazines and
talks will be given at the major short courses in the U.s.
African Violet - Production conditions were not evaluated on
African Violets. Two varieties were obtained from a commercial grower at
marketing stage and placed into our interior rooms at either 65, 70 or75 F
with 50 or 100 ft-c. of light, 12 hours daily. Plants remained in these
conditions for 62 days. The number of open flowers was counted daily. The
results were surprising! Within 14 days on ‘Wyoming’ and 35 days on
‘Michigan’, plants held at 70 F and 100 ft-c. had more flowers than
the other treatments. By day 62, ‘Wyoming’ plants in these conditions
had 3-4 times more flowers (18) than the other light/temperature
treatments. Treatment differences were not as great on ‘Michigan’
plants.
3. Next steps and future for project and anticipated industry
benefit(s).
We will continue to evaluate longevity of different flowering potted
plants in order to provide all segments of the industry with information
on practices to maximize quality and longevity for the consumer. In
addition, we will be building ethylene gas chambers so we can evaluate
these practices under conditions characteristic of storage, transport and
retail display so that the effects of ethylene will be more
understandable. Then, we can provide information on differences between
ethylene sensitivity and generation and procedures to reduce the effects.
The results of this research will be published in trade magazines and
talks will be given at the major short courses in the U.S.
