North Carolina

Flower Growers'

BulletinVolume 43, Number 4

August, 1998

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Official Publication of the North Carolina Commercial Flower Growers' Association

Field Production of Cut Flowers: a Primer

Part II

Holly L. ScogginsDept. of Horticultural Science, NC State University

Thefirst part of this article appeared inthe June 1997 issue of the NCFG

Bulletin and presented an overviewof marketing, production costs, and informationresources. Part II focuses on production cultureand postharvest requirements.

PRODUCTION

The ideal site for cut flower production is infull sun with wind protection, an irrigation source,and easily accessible. Raised beds are virtuallyrequired to ensure proper drainage (unless thesoil is very sandy). Beds can be any length. Ifoffering cut-your-own, it needs to be narrowenough for customers to reach comfortably to themiddle of the bed. A height of 4 to 8 inchesshould suffice, and drainage can be enhanced byburying drain lines 12" underneath the beds.Break up the hardpan or clay layer at least 1.5 to

2 feet deep with a subsoiler. Proper preparationof the beds is essential to optimum growth andyield. Amend beds with plenty of organicmaterial. Well-composted horse or cow manureis excellent. Be sure it has aged to the point whereweed seeds are no longer viable. Incorporatelime, superphosphate, and other nutrients asrecommend by the results ofyour soil test. Thereis no excuse for guessing as to the soil nutrientcontent. Soil samples are analyzed at no chargeby the NCDA Agronomic Services Division,Raleigh, NC [919.733.2655].

If any of the beds are to lay fallow for a lengthof time, such as over winter, cover crops areexcellent for increasing theorganic matter contentof the soil and reducing erosion. Recommendedfall and winter cover crops for North Carolinainclude hairy vetch, rye, barley, and crimsonclover; or better yet, a combination of two or

N.C. Flower Growers' Bulletin - August, 1998

more of these crops. Summer cover crops caninclude soybeans, cowpeas, buckwheat, andsesame.

Mulch has its proponents and detractors.Some growers insist on it for weed suppressionand moisture retention. Others prefer to tillbetween rows to control weeds. Because of the

enormous variety ofspecies grown as cut flowers,no single herbicide can be recommended.

Plant material can be acquired from a numberof sources. Annuals can be direct sown into the

bedsor transplantedas plugs (whether bought-inor produced on-site). Some annual species shouldbe seeded in succession to continuously produceas long as the growing season allows. Perennialsare best started from plugs, whether seed orvegetatively propagated. There are manycommercial sources for large plugs and starterplant liners. If perennial species are planted outin the spring, be sure they have been vernalized(cold treatment to induce flowering) if thatparticular species requires it in order to flowerthat season. For some slow-growing species, youmay want to start with at least 4" to 1 gallonmaterial. Crop rotation for annuals is a goodidea. Change sites to reduce the incidence ofsoil-born pathogens.

Optimal spacing varies between species.What seems adequate spacing for a row ofperennials the first year may result inovercrowding the following year. Dense spacingcan lead to hi "her incidence of disease as air

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circulation is limited. Conversely, too muchspace is an invitation to weeds and reduces yieldper square foot. Note that dense planting oftenencourage longer stems. The spacing of annualsvaries by species, ranging from 4 to 6" centers to1'x 1'. Be sure to thin rows to proper final spacingif direct seeded. Depending on the species'particular vigor, recommended spacing forperennial species range between Vx I' and 2' x 2'.or 1' between plants and 2 to 3' between rows.Woody plants should be placed on 3 foot centerswith more aggressive or larger species on 5 footcenters. Maintain moist conditions until plantsare well established. Division is beneficial (orimperative) for many perennial species after thesecond year of production in order to maintainproductivity.

Tall or relatively "top heavy" species willrequire stem support. Rig beds with adjustablewire or plastic netting that can be raised as plantsmature. Be sure the netting and supports are inplace before the plants get too tall. It's extremelydifficult to "retrofit" support without damagingthe plants.

Many species, such as Phlox paniculata,benefit from pinching to encourage branchingand obtain the maximum number of stems perplant. Pinch as soon as the plants are well-established and elongating. Leaving some of thecrop unpinched can result in earlier floweringand larger flowers with the trade-off of fewerstems. Consult crop-specific references fortiming.

Fertilizer requirements differ from crop tocrop. Some annuals, such as the annual sunflower(Helianthus animus) are heavy feeders and requireperiodic fertilization throughout the growingseason. Fertilizer delivery methods range frombroadcast or side dress application of granularfertilizer to fertigation (application of nutrientsthrough the irrigation system). Incorporation of aslow-release fertilizer during Spring (not Fall)tilling will give young plants a jump-start.Periodic on-site monitoring of soil and irrigationwater pH and soluble salts will be a tremendous

N.C. Flower Growers' Bulletin - August, 1998

help in designing and adjusting an appropriatefertilizer program. Limited space does not allowa full discussion on fertilizer sources and

recommendations. Consult the cited references

or your local cooperative extension service.Pests for field grown cut flowers run the

evolutionary gamut, from powdery mildew,aphids and Japanese beetles, to rabbits, deer, andunscrupulous passersby. Fungicides, pesticidesand shotguns are all of use in the battle formaximum yield. IPM (integrated pestmanagement) is highly recommended as a money-saving and environmentally acceptable pest andpathogen control methods for field cut flowerproduction. If you are using only organic meansor biological controls to produce your crop, tellyour customers! Use it as a marketing edge. TheDisease, Insect, and Related Pest section of theFloriculture home page web site (www2.ncsu.edu/floriculture/) offers several publications ofrelevance to cut flower producers concerningIPM and insect/disease identification and control.

HARVEST

Caveat: In warm weather, it is imperativethat field-grown cut flowers be harvested early inthe morning. This is not a business for those whoare slow to rise or favor lingering over the morningpaper... Harvest when plant water status is highand temperatures and transpiration are relativelylow. Wait until dew or other moisture has

evaporated, if possible. Wet flowers and foliageare more susceptible to postharvest pathogens.Do not harvest when light level and temperatureis at a maximum. Shading the freshly harvestedmaterial also helps maintain lower temperatures.

Harvesting at the proper stage ofdevelopmentfor each species is very important. Too early, andsome species may not open; too late can result indrastically reduced vase lifeor shipability.Harvestis the most labor-intensive aspect of cut flowerproduction. Communication with your harvestworkers is essential! Be clear about what is

acceptable and what isn't to insure uniformity ofthe product.

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Field and handling sanitation is just asimportant as it is in the greenhouse business.Keep fertilizer injector systems, harvest knivesor shears, postharvest handling buckets, surfacesand coolers clean and sanitized. Do your cutting,grading and bunching in one "fell swoop" toeliminate excess handling which can increase thecut's exposure to pathogens and water stress.

POSTHARVEST HANDLING

Proper postharvest care of your cuts isessential for maintaining high quality and a longvase life. The plant's life processes continueeven after the stem is cut; respiration,transpiration, growth and development stillhappen. The cut stems and flowers remainsensitive to damage and disease. Floralpreservatives and other additives are a necessarypart of the postharvest process. Refer to specificrecommendations for each species.

Cool water can serve to promote cooling ofthe stems. Warm water is useful if the cuts are

under extreme water stress. Monitor water pH -acidic water (pH 3.0 to 5.5) inhibits bacterialgrowth helping flowers persist longer.Preservatives are also formulated to be effective

at lower pH. Mixing your own postharvestpreservative concoctions is not recommended.There are many sources for flower preservatives,conditioners, hydrators, and ethylene inhibitors.

Ethylene is another important considerationaffecting postharvest longevity. Flowers cannotbe stored with any kind offruit or vegetable. Theethylene produced by the fruit or veggie willresult in premature floral senescence. Goodventilation and removal of senescent flowers is

essential to maintain a relatively ethylene-freeenvironment.

GRADING, PACKING, AND DELIVERYThere is no mandatory grading system for

specialty cuts flowers in the U.S. Voluntarygrading standards exist for the major cut flowerspecies as established by the Society of AmericanFlorists. General rules of thumb apply, however,

N.C. Flower Growers' Bulletin -August, 1998

emphasizing uniformity: no greater than 10%deviation in stem length, relative uniform stemdiameter, flowers of uniform size and stage ofdevelopment. Ten stems per bunch is the standardfor most species, with some species sold in fivesor as singles.

There are myriad packing options - buckets,boxes, flowers held wet or dry; find out which areappropriate for the species you are growing. Beaware that some species such as snapdragon andgladiolus exhibit a (negative) geotropic response.Stems laid flat will bend upwards, away from thegravitational pull, resulting in curved stems.

Vehicular and personnel requirementsnecessary for timely deliveries are oftenoverlooked in the planning of a cut flowerbusiness. Things can get complicated (andexpensive), reducing efficiency and profits. Onealternative is to delivery directly from the field inthe morning. This works fine for immediatedelivery to local markets. However, if you needto hold the flowers for any reason, such asaccumulating certain cuts for a larger wholesalemarket, cold storage facilities will be necessary.There are many options available at a wide rangeof costs - built-in-place coolers, prefabricatedcold storage units, or even modified refrigeratedtransportation units such as refrigerated semi-tractor trailers or ice cream trucks. If using anindependent shipper, be sure your carrier iseducated to the need to maintain temperaturesbetween 35 and 40 °F during transit.

Cut flower leftovers? There are numerous

ways to preserve and make use of surplus cuts -air drying, oven drying, silica gel, glycerin, etc.A number of publications include this subject -see the list of references at the end of this article.

ORGANIZATIONS

The Association of Specially Cut FlowerGrowers is "the" association to join. Quarterlynewsletter that accompanies membership is anexcellent resource for new crop information,marketing tips, industry news and researchupdates. For more information, contact: ASCFG,

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Inc., PO Box 268. Oberlin, OH 44074, Ph.

216.774.2887.

Numerous state floriculture and greenhouseassociations (often associated with the state's

extension service) publish excellent newsletters.For the price of a (nominal) membership fee, up-to-date research and grower experiences can beyours! Visit your local botanical gardens/arboreta/field trials for the first glimpse of new species andcultivars. I've mentioned this before, but the

world wide web is becoming a truly useful sourcefor contacts and information. Equipment andfloral wholesalers, agricultural chemicalcompanies, agricultural extension agencies areall entering the Internet market with gusto!

UPCOMING CULTURAL TABLE

Due to space constraints, we were unable toinclude a cultural summary table in this issue ofthe Bulletin. It will appear in the next issue. Thistable is an intended as an overview of some of the

widest-grown species suitable for field productionof cut flowers in the Southeast. Planting andbloom dates will obviously vary by zone, consultthe following references for more detailed culturaland postharvest information. Some species arebest suited for greenhouse production or needcooler temperatures than our growing seasonprovides - e.g. freesia, carnation, Gypsophila,etc. -and have not been included in the table. The

table is adapted from Armitage (1993, 1997),

N.C. Flower Growers' Bulletin - August, 1998

Stevens (1996), and various articles from the CutFlower Quarterly (ASFGS, Inc.) newsletters.

REFERENCES AND RECOMMENDED

READING

Armitage, Allan M. 1993. Specialty Cut Flowers.The production ofannuals, perennials, bulbsand woody plants for fresh and dried cutflowers. Varsity Press/Timber Press,Portland, OR Ph. 800.327.5680. A to Zproduction information from the leader indiscovery and development ofspecialty cutflowercrops. Coveragebygenusandspeciesincludes propagation, environmentalrequirements, field and greenhouseperformance, harvest and postharvest, andpests and diseases.

Armitage. Allan M. 1997. Herbaceous PerennialPlants. 2nded. Stipes Publishing, Champaign,IL.

Dirr, M.A. 1990. Manual of Woody LandscapePlants: Their Identification, Ornamental

Characteristics, Culture, Propagation andUses. 4lhed. Stipes Publishing, Champaign,IL. The definitive guide to woodyornamentals in the U.S. Useful culturalinformation for woodyplants with "specialtycuts " potential.

Volume 43, Number 4

Gast, K.L.B., et al., 1994. Cold Storage forspecialty cut flowers and plant material (MF-1174), Cooperative Extension Service,Kansas State University, Manhattan. Howto build your own cooler!

McAvoy, Richard J. 1997. Annuals for Field-grown Cut Flowers. ConnecticutGreenhouse Newsletter 197:1-8.

Reid, Michael and Linda Dodge. 1996. CutFlowers: Postharvest Handling Review. In:The Cut Flower Quarterly. 8( 1):23-24.

Stevens, Alan. 1996. Field Grown Cut Flowers:

A Practical Guide & Source book. Avatar's

World Ph. 800.884.4730. Focuses on

management, marketing and productionwith some specific crop information,mistakes to avoid, and reams ofsources anddirectories. Dr. Stevens is a noted cut

flower specialist and consultant.

Note that the ASCFG's national meeting willbeheld in Raleigh, NC, October 28-31. The

conference will include workshops on growing,marketing, and what's hot, plus a great trade show.

Contact Brian Whipkerfor more information.The author wishes to thank the countless growercontributions to the Cut Flower Quarterly that

helped comprise this article.