Date 8/27/92

Title of Project Postproduction Longevity of Potted Bulbs

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

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

Anticipated Date of Project Completion/Final Report December 1994

Individual(s) Conducting Project:

(List Project Leader First)

T. A. Nell - Title Professor

Telephone Number (904) 392-1829

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, 8/27/92

A. Project Objectives:

1. To relate physiological parameters (photosynthesis, dark respiration, carbohydrate levels) to

increased longevity of flowering potted plants.

2. To develop methods to incorporate results of physiological studies into commercial practices.

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

requirements for forced bulbous plants.

B. Summary of Work Completed:

1. Starch analysis of poinsettia cyathia during the post production period has been completed.

These results complement previous sucrose, fructose and glucose results.

2. Studies are continuing on longevity of sucrose supercharged potted roses. Sucrose is being

injected into potted roses and the effects on respiration and longevity are being monitored.

Longevity differences between rose varieties and the relationship to respiration is being

monitored.

3. Work in number 2 above showed a time of year difference, possibly due to temperature,

photoperiod or production light level. Studies have been conducted and are currently being

repeated to assess photoperiod and temperature effects to longevity.

C. Results to Date:

1. Potted rose flower respiration has been related to longevity of individual buds/flowers and to

varietal differences.

2. Potted rose flowers lasted longer on several varieties with greater light energy input and warm

temperatures — light and temperature had little, if any, affect on other varieties.

D. Future Plans Covered by the Endowment Grant:

1. We are using radioactive carbon to trace the translocation of sucrose injected into the stem.

Studies have begun and will be complete in early 1993.

2. Radioactive calcium will be used to track calcium movement in poinsettia bracts and relate this

problem to calcium deficiency.

3. We have initiated a project to determine the relationship of total protein content and specific

proteins to longevity of potted chrysanthemums. Presently, we are developing techniques for

this work. As with the carbohydrate research, the protein research will allow us to predict the

longevity of potted flowers at the time of sale. In the past, protein analysis has been related

only to the final phases of flower senescence in ethylene sensitive flowers.

E. Anticipated Benefits for Floral Industry:

Cultural practices developed as part of this AFE grant are providing growers with methods to

provide customers with higher quality, longer lasting flowering potted plants. In addition, the

current work with physiological factors affecting longevity provides a long term means of

directing breeding programs and modification of environmental conditions for maximum

longevity.

F. Additional Information/Publications:

A large number of growers are now using cultural practices generated by this project. This

information has significance to growers, wholesalers, retailers and mass marketers. Every

attempt is being made to get the information into trade publications.

---

HOLLAND FLOWER BULB TECHNICAL SERVICES

Published by the Netherlands Flower-Bulb Institute

January 1992

POST-GREENHOUSE (CONSUMER) REQUIREMENTS FOR ROOTING ROOM BULBS FORCED

AS POTTED PLANTS

Prepared by:

Dr. T Nell and Dr. J. Barrett

Department of Ornamental Horticulture

University of Florida

Gainesville, FL 32601

and

Dr. A.A. De Hertogh

Department of Horticultural Science

North Carolina State University

Raleigh, N.C. 27695-7609

I. Objective of the trails

To determine the post-greenhouse temperature and light requirements that will maximize the

potted life of forced rooting room flower-bulbs under home conditions.

II. Procedures

A. Programming and greenhouse conditions.

All the flowering bulbs were forced at N.C. State University utilizing the programming and

greenhouse conditions described in the 4th edition of the Holland Bulb Forcer’s Guide. A sterilized

planting medium consisting of equal parts pine bark, soil, peat and sand and pH 6.8 was used.

B. Removal from greenhouse.

Each type of flower bulb was removed from the greenhouse in the ‘Bud’ stages of floral

development that are illustrated in the attached pages.

C. Storage before packing and shipping.

If required, the plants were placed in the ‘Bud’ stage of development, at 35′F (2′C) until packed in

the boxes.

D. Packing.

All plants were placed in waxed floricultural shipping boxes.

E. Shipping.

After packing, boxes were placed at 35′F (2′C) until picked up and transported under refrigerated

conditions to the University of Florida. Normally, the transportation period was 3-4 days.

F. Handling after arrival.

Plants were removed from the shipping boxes, graded and then placed in controlled environmental

rooms under the following conditions.

Temperature	Light intensity
65′F (18′C)	50 ft candles
65′F (18′C)	100 ft candles
70′F (21′C)	50 ft candles
70′F (21′C)	100 ft candles
75′F (24′C)	50 ft candles
75′F (24′C)	100 ft candles
Planting medium was watered daily under all conditions.

III. Results

The basic results and practical implications for each bulb species evaluated are summarized in the

attached pages.

IV. Acknowledgements

We wish to acknowledge the following organizations who have supported this research effort:

A. Amarican Floral Endowment

B. Dutch Bulb Exporter’s Association

C. Armellini Express Lines

D. Nurseryman’s Exchange

CROP I

GENERAL ASPECTS

1. Crop - Daffodil (Narcissus spp.)

2. Cultivars Used

‘Bridal Crown’ (Orange center, White perianth)

‘Ice Follies’ (Cream cup, White perianth)

3. Optimal stage for

Marketing Daffodil (Narcissus)

as Flowering Plants

(Figure on right).

RESULTS OF POST-GREENHOUSE TRIALS

	Days of Potted Life
	65′F (18′C)		70′F (21′C)		75′F (24′C)
Cultivar	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.
‘Bridal Crown’	18	18	14	14	11	11
‘Ice Follies’	10	10	8	8	7	7

CONCLUSIONS AND PRACTICAL SIGNIFICANCE

Daffodil plants had excellent longevity at 65′F (18′C). For best interior performance in retail areas, plants

should be displayed at 41′F (5′C). While in the home plants should be held between 65-70′F (18-21′C).

CROP II

GENERAL ASPECTS

1. Crop- Crocus

2. Cultivars Used

‘Pickwick’ (White, Striped Purple)

‘Remembrance’ (Lavender)

3. Optimal stage for

Marketing Crocus

as Flowering Plants

(Figure on right).

RESULTS OF POST-GREENHOUSE TRIALS

	Days of Potted Life
	65′F (18′C)		70′F (21′C)		75′F (24′C)
Cultivar	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.
‘Pickwick’	8	8	7	8	6	6
‘Remembrance’	9	8	9	9	8	8

CONCLUSIONS AND PRACTICAL SIGNIFICANCE

Crocus flower longevity was increased approximately 25% by maintaining plants at 65′F (18′C) when

compared to 75′F (24′C), the flower color faded at the higher temperature. In retail areas, plants should be

displayed at low temperature 41′F (5′C), while in the home plants should be held between 65-70′F

(18-21′C), and preferably lower.

CROP III

GENERAL ASPECTS

1. Crop - Hyacinth (Hyacinthus orientalis)

2. Cultivars Used

‘Amsterdam’ (Pink)

‘Ostara’ (Blue)

3. Optimal stage for

Marketing Hyacinths

as Flowering Plants

(Figure on right).

RESULTS OF POST-GREENHOUSE TRLALS

	Days of Potted Life
	65′F (18′C)		70′F (21′C)		75′F (24′C)
Cultivar	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.
‘Amsterdam’	10	10	8	9	7	7
‘Ostara’	17	17	12	13/TD>	12	12

CONCLUSIONS AND PRACTICAL SIGNIFICANCE

Stem topple occurred at all temperatures and light levels, but was greatest at the low temperature (65′F/18′C),

an Ethephon treatment applied, during the greenhouse phase minimized stem topple at all temperatures.

In retail areas, plants should be displayed at 41′F (5′C), while in interior areas plants should be

held at temperatures between 65-70′F (18-21′C) with at least 50 ft. c. of light for optimal longevity.

CROP IV

GENERAL ASPECTS

1. Crop - Dwarf Iris (Iris reticulate)

2. Cultivars Used

‘Harmony’ (Deep Blue)

3. Optimal stage for

Marketing Dwarf Irises

as Flowering Plants

(Figure on right).

RESULTS OF POST-GREENHOUSE TRIALS

	Days of Potted Life
	65′F (18′C)		70′F (21′C)		75′F (24′C)
Cultivar	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.
‘Harmony’	6	6	5	5	4	4

CONCLUSIONS AND PRACTICAL SIGNIFICANCE

Dwarf Irises were short lived but maintaining plants at 65′F (18′Q increased longevity 50% compared to

75′F. Flowers will open rapidly during transport if packed after the optimal stage for marketing or if shipping

temperature exceeds 35-38′F (2-3′C). In retail areas, plants should be displayed at 35′F (2′C).

CROP V

GENERAL ASPECTS

1. Crop - Muscari armeniacum (Grape Hyacinth)

2. Cultivars Used

‘Early Giant’ (Blue)

3. Optimal stage for

Marketing Muscari armeniacum

as a Flowering Plant

(Figure on right).

RESULTS OF POST-GREENHOUSE TRIALS

	Days of Potted Life
	65′F (18′C)		70′F (21′C)		75′F (24′C)
Cultivar	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.
‘Early Giant’	27	27	22	24	15	15

CONCLUSIONS AND PRACTICAL SIGNIFICANCE

Muscari will provide good interior longevity if held between 65-70′F (18-21′C) in the interior environment. In

retail areas, plants should be displayed at 41′F (5′C).

CROP VI

GENERAL ASPECTS

1. Crop - Tulip (Tulipa spp.

2. Cultivars Used

‘Capri’ (Red)

‘Monte Carlo’ (Yellow)

3. Optimal stage for

Marketing Tulips

as Flowering Plants

(Figure on right).

RESULTS OF POST-GREENHOUSE TRIALS

	Days of Potted Life
	65′F (18′C)		70′F (21′C)		75′F (24′C)
Cultivar	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.	50 ft. c.	100 ft. c.
‘Capri’	14	14	12	12	9	10
‘Monte Carlo’	17	17	13	14	10	10

CONCLUSIONS AND PRACTICAL SIGNIFICANCE

Tulip flowers open rapidly, flower color was faded and longevity was reduced at 75′F (24′C). Plants must be

marketed at the proper stage and held between 65-70′F (18-21′C) in the interior environment for optimum

longevity. In retail areas, plants should be displayed at 41′F (5′C).

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