Date February 26, 1992

Title of Project Postproduction Longevity of Potted Bulbs

Institution where work is being conducted University of Florida and North Carolina State Univ.

Amount of Endowment Grant $11,000
Covering Period 01/01/92 to 12/31/92

Anticipated Date of Project Completion/Final Report December 1993

Individual(s) Conducting Project:

(List Project Leader First)

T. A. Nell - Title Professor

Telephone Number (904) 392-7933

A, A. DeHertogh - Title Professor

J. E. Barrett - Title Professor

Postproduction Longevity of Potted Bulbs

Terril A. Nell, Gus DeHertogh and James E. Barrett

University of Florida and North Carolina State University

Progress Report to the American Floral Endowment, 2/26/92

A. Project Objectives:

1. To determine the effective home-life of selected non-rooting room forced bulbs and tuberous

flowering potted bulbs.

2. To determine the eff ect of shipping temperature and duration on longevity and bud drop of potted

Asiatic Lilies.

3. To establish the optimal post-greenhouse light and temperature requirements for

forced bulbous plants.

B. Summary of Work Completed:

1. Forced Paperwhite Narcissus plants were shipped in

the fall season. Astilbes, Caladiums, Dahlias, and Lilies will be

shipped in Spring, 1992.

2. Forced paperwhite Narcissus were shipped to Gainesville for post-greenhouse evaluation in the

fall season and again in January and February.

3. Astilbes, Caladiums, Dahlias and Lilies will be shipped later this spring.

C. Results to Date:

1. At the present time, we have results only for one shipment of Paperwhite Narcissus. Generally,

the Paperwhite Narcissus are lasting in excess of two weeks, with plants at 75 lasting a shorter

period of time than those at 65 or 70′F. as with many of the other bulbs, interior light level is

having little effect. Flower stalk elongation has been a problem at all temperatures and light

levels.

D. Future Plans Covered by the Endowment Grant:

1. Astilbes, Caladiums and Dahlias will be shipped this spring for evaluation at various interior light

and temperature levels.

2. We are trying to obtain additional Amaryllis bulbs to repeat the work with ethephon treatments

for reduction of stalk elongation.

E. Anticipated Benefits for Floral Industry:

Potted bulbs offer the consumer an excellent product for fall and spring holidays and floral sales.

These results illustrate the importance of maintaining flowering bulbs at cool temperatures

throughout the post-greenhouse phase. This information should be useful in floral marketing

programs.

F. Additional Information/Publications:

Information from this project has been published in Grower Talks (attached) and in Floraculture

International magazines (with The Endowment Logo) and a Technical Services Bulletin is being

printed in Holland and will be circulated to bulb forcers throughout the United States.

We will be presenting two papers in May at the International Bulb Conference in Poland with

information generated by this project.

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Bulbs as Flowering Potted Plants — Keys To Increased Longevity

by Terril A. Nell, A. A. DeHertogh and Jim Barrett

Bulbs sold as flowering potted

plants are popular at Valentine’s

Day and boost weekly floral sales

in retail florists and supermarkets

throughout the spring season. They

herald the beginning of spring in the

southern United States and offer a

fragrant promise of spring to residents

in the North who are still enduring

winter chills.

Bulbous plants were sold in the past

primarily as cut flowers or for garden

plantings. Cut flower bulb sales still

dominate European commercial sales,

in the last 25 years, North American

growers gained information, primarily

through the Holland Bulb Forcers Guide,

that permits successful potted bulb

programming and forcing. Refining of

bulbs’ cultural requirements is underway. Large quantities of potted bulbs

are being sold through mass market

outlets; over the past five to eight years

this has stimulated the development of

postproduction handling guidelines.

These will enable growers and retailers

to improve performance and extend

longevity.

By marketing potted flowering bulbs at the right stage of development and maintaining plants in cooler retail desplays,

you can improve quality and increase sales.

Cultural practices affect the longevity of most flowering plants, but

production factors haven’t been shown to

significantly affect flowering potted

bulbs’ longevity. Quality in terms of

aesthetic appearance is clearly related,

however, to certain cultural practices.

Application of Ethephon to hyacinths,

for instance, reduces stem topple, a

common disorder in this popular

flower bulb.

Three factors-the cultivar, stage of

floral development and storage and

display temperatures have the greatest influence on flowering potted bulb

interior performance and longevity.

Stage of development — a critical factor

The stage of floral development at

marketing time has a significant impact

on flowering bulb longevity. Most

bulbs should be sold before significant

color is showino in the flower and prior

to the first flower’s opening. Too often,

flowering bulbs are sold when already

fully open. While marketing at this

stage enhances retail displays, it greatly

compromises interior longevity.

Marketing flowering bulbs that are

too open often results from improper

timing, poor storage conditions or exposure to warm temperatures.

Flowering bulbs can be stored for up to 14

days without affecting longevity, provided the temperature is accurately

maintained at 33′F to 35′F for rooting

room bulbs and no less than 50′F for

amaryllis. Storing rooting room bulbs

at warmer temperatures will hasten

flowering and decrease longevity. Amaryllis, a tropical bulb, is more sensitive

to cold and subject to chilling injury at

temperatures below 50′F.

Flowering bulbs require cooler display temperatures

Temperature is the controlling factor

in obtaining maximum shelf life tor

potted spring flowering bulbs. In our

studies, Capri tulips lasted 18 days

when displayed at 65′F and only eight

days at 80′F. Similarly, hyacinths lasted

approximately 13 days at 65′F and only

five days at 80′F. Even greater reductions in longevity would have resulted

if plants had been exposed to these

evaluation temperatures with fully

open flowers.

Display/consumer light levels between 50 and 100 foot-candles had little

effect on these flowering potted bulbs’

longevity. Excessively low light levels,

below 50 f.c., may result in excessive

stem elongation and reduced longevity, however, especially at warmer

temperatures.

Marketing changes needed

The importance of maintaining cool

display temperatures poses a dilemma

for the retailer. In most retail outlets,

flowering bulbs are displayed together

with potted chrysanthemums and

other flowering plants with greater

tolerance for warm interior temperatures and greater longevity under

warmer conditions. It may be necessary

for successful retailers to utilize refrigerated display coolers for flowering

potted bulbs, just as for roses and other

cold-requiring cut flower displays.

Three factors affect longevity — stage of development, the cultivar and temperature.

Retailers can also enhance flowering

potted bulbs’ value by providing specific directions for maintenance in the

home or office. Ideally, consumers

should maintain potted bulbs at 68′F

during the day and move the plants to

a cool 55 to 60′F area in the evening to

increase floral longevity.

Marketing bulbs at the proper stage

of development and providing proper

handling conditions can increase longevity to 14 days for most flowering

potted bulbs, enhancing the appeal of

these crops to consumers.

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