University of Vermont Extension
Department of Plant and Soil Science

Postharvest Handling of Field Cut Flowers (COH 29)

Leonard P. Perry, Extension Professor


Keys to longest vase-life (postharvest longevity)

-sufficient sugars/carbohydrates

-sufficient water

-maximize through proper conditions at all stages: pre-, during, post harvest

-goal of all: minimize stress ® increase vase-life

Pre-harvest/Production factors affecting post-harvest life, quality

soil--proper for plants, or stress created

fertility--adequate, not excessive

light--ensure best possible, appropriate for plant

temperature-- cool prior to harvest is ideal if possible, more carbohydrates (sugars and other reserves to help plants last)

moisture--plants should be turgid, well-watered prior to picking, and through season

pests--create stresses, more importantly make flowers unsalable

Time/Stage of harvest

(optimum, may vary with marketing)

time of day: -flowers that lose water rapidly harvest early in morning, after dew dries so don't stay wet and get disease

-others harvest early in morning or evening, latter best as most sugars late in day

temperature: cool or cloudy best (less transpiration/water loss)

stage: -varies with individual species, see references

-may vary with marketing purpose or customer/broker desires (more open for direct retail or certain florists, or often for drying)

-longest vase-life from certain stages, based on flower development from tight (peonies) to just opening (such as daisies and spike flowers, if in doubt for species use this) to fully open (yarrows)

into?: immediately at least into water, preferably for many into preservative

Postharvest factors affecting vase-life

light--presence decreases, uses up carbohydrates (sugars)

moisture--higher better, 60-80%RH, less transpiration (loss of water through leaves)

temperature--cooler generally better, 40ºF, less water loss and depletion of sugars

-cool before packing, can be done with cool water

-warm water (100-110ºF) to rehydrate if wilted, also to speed opening

-don't freeze

-most tropicals, few perennials, keep above 50ºF

water quality--keep clean, replace every 3-4 days

-elements in water may be factor: fluorides injure some (gerbera, freesia)

-tap vs. distilled? no real difference, in studies at UVM:

-no significant difference for 16 species using Burlington tap water

-among 3 asters and one phlox tested, and 12 sources from across U.S., only one aster had significant differences (5 days), 2 sources yielded longer vase-life when Oasis preservative also used

-pH acid (3.0-5.5) best: deters growth of microorganisms which clog plant stems, flowers take up acid water quicker, most floral preservatives work best at

-low alkalinity below 200ppm is best to avoid problems

-testing at state university labs, private labs (see suppliers), on-site kits:

Hach Company, Loveland, CO 303-669-3050


Typical analysis of tap water (Burlington, VT), units in ppm, 8/18/89

P 0.00 K 1.12 Ca 18.20
Mg 4.25 Mn 0.00 Fe 0.00
Cu 0.037 B 0.00 Zn 0.00
Mo 0.00 Al 0.03 Na 12.2
pH 7.47 salts 0.18 alkalinity 66.7
chlorides 11.7 fluorides 0.00  


gases--ethylene bad for many flowers, many close ("go to sleep" as in carnations)--age prematurely

-avoid storing with fruits, vegetables; also produced by damaged tissues, aging flowers so keep old flowers away/compost, ventilate storage

-STS (silver thiosulfate) usually helps prevent damage

recutting stems--tend to become blocked with bacteria, air bubbles

-recut stems under water, cutting 1" off base, every 3-4 days; may not be needed (as with 3 species tested at UVM) but good insurance and can only help

-use clean containers, warm acid water helps reduce air bubbles

-probably best to replace preservative; in UVM studies added 2+ days to life

storage--minimize, follow above, maximum 3-5 days

Preservatives

Purpose-- keep water acid, provide sugars, some-- counteract ethylene effect

Types--most home remedies like aspirin, little or no effect; effective is 50:50 v/v lemon-lime soda and water (acid, provides sugars) but expensive for commercial

-which is best? in studies at UVM varied with species, for some tap water was no different, Oasis and Floralife and Rogard among top treatments tested

-main point: use a preservative, in most cases beneficial, and in many cases (sources, species) better than tap water

Products: (some key sources as examples, check with supplier for more)

-Floralife, 800-323-3689

-Gard, 800-433-4273

-Pokon and Chrysal, 800-247-9725

-Smithers Oasis, 330-673-5831

STS--silver thiosulfate, counteracts effects of ethylene on sensitive flowers

-"pulse" or simply put in solution for about an hour, remove, rinse and place in final solution

-may not be needed/useful if no exposure to ethylene (as with 3 species at UVM), but unless can guarantee this should be used

-may need to consider disposal options to minimize environmental effect, check with supplier for recovery systems and recycling centers for options


Flowers Sensitive to Ethylene

Achillea Aconitum Agapanthus
Allium Alstroemeria Anemone
Antirrhinum Aquilegia Asclepias
Astilbe Bouvardia Campanula
Carnation Celosia Centaurea
Chelone Consolida Delphinium
Dianthus Dicentra Digitalis
Eremurus Eustoma Freesia
Godetia Gypsophila Iris
Kniphofia Lathyrus (Sweet Pea) Lavatera
Lilium Limonium Lupinus
Lysimachia Matthiola (Stock) Phlox
Penstemon Physostegia Ranunculus
Rosa Rudbeckia Salvia
Saponaria Scabiosa Sedum
Silene Solidago Thalictrum
Trachelium Tricyrtis Triteleia
Trollius Veronica Veronicastrum


References

-Armitage, Allan. 1993. Specialty Cut Flowers. Varsity/Timber Press, Portland.

-Gelein, Coen and Nees Joore. 1988. Decorative Cut Flowers. Cassell Publ, London.

-Nowak, Joanna and R. Rudnicki. 1990. Postharvest handling and storage of cut flowers, florist greens, and potted plants. Timber Press, Portland.

-Perry, Leonard. 1998. Herbaceous Perennial Production: A Guide from Propagation to Marketing. NRAES, Cornell, Ithaca, NY.

-Sacalis, John. 1993 (1987). Postproduction series--cut flowers. Grower Talks Bookshelf. Batavia, IL.

-Stevens, Alan. 1997. Field Grown Cut Flowers. Avatar's World, 106 E Hurd Rd, Edgerton, WI 53534, 800-884-4730.

-Vaughan, Mary Jane. 1988. The complete book of cut flower care. Timber Press, Portland.

*Association of Specialty Cut Flower Growers, MPO Box 0268, Oberlin, OH 44074,

440-774-2887, http://www.ascfg.org

directory of suppliers and members, newsletter, meetings

*Perry's Perennial Pages: http://www.uvm.edu/~pass/perry/


Return to Perry's Perennial Pages

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. Lawrence Forcier, Director, UVM Extension System, Burlington, Vermont. University of Vermont Extension System and U.S. Department of Agriculture cooperating, offer education and employment to everyone, without regard to race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial status.

Created 12/10/98