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Answers to Your Burning Postharvest Questions
Alicain Carlson, John Dole, Iftikhar Ahmad, ,North Carolina State University
Overview of TopicsOverview of Topics
General Postharvest Handling Harvest Time of Dayg
Effects and Control ofWater Quality Effects and Control of Ethylene
Species Evaluations: Celosia, Eremurus, Marigold SnapdragonMarigold, Snapdragon
General Postharvest Handling
Maximizing Postharvest LifeMaximizing Postharvest Life
There are many factorsThere are many factors that effect vase life of cut flowers: Pre‐harvest Harvest General Post‐harvest
QualityQuality
Poor quality declines fasterPoor quality declines faster
CultivarCultivar20 Water
12
16
WaterHolding
8
12
0
4
bel ht mi
ble er ry on on …
ze ra ja ld ze ow ny ge oy ta er ca ne ce sh ar
Arb
First Lig
alilee Ad
amGoldy
Dou
bmon
Sum
me
Orange Glo
mium Lem
ot R
ed/Lem
orocut B
reez
Sola
Son
Stella Go
mmer Breez
emon
Yello
Sunn
nrich Orang
Tavor Jo
Terracot
The Jok e
Tosc
Valentin
ncen
t Cho
icVincen
t Fres
Zoh
G GLem O
Prem
Pro Cu
t P
Sum
Sun4
U Le
Sun
Vin V
Developmental stageDevelopmental stage
Harvest at Harvest at optimum stage to
i imaximize postharvest life Varies with market
– Direct to consumer– Retailers– Wholesalers
CarbohydratesCarbohydrates
Sugars fuel plantsg p Highest levels possible Effects:
– Open buds– Develop, maintain color
Sources:– Made by the leaves, stored in the stemsto ed t e ste
– Provided by the grower in a postharvest solution for cutsfor cuts
TemperatureTemperature
The warmer the The warmer the temperature:– Faster the respiration rate
– Faster bacteria grow
–More stems bend after storageStem bending in Gerbera after storage g
Temperature Drives RespirationTemperature Drives Respiration
For every 10oC increase in temperaturey p– Respiration rate doubles– One day vase life is lost
G t fi ld h t t ASAP Get field heat out ASAP Set cooler at 34 to 38oF
Close to 32oF is optimum for most speciesClose to 32 F is optimum for most species 34‐35oF or 34‐38oF is more practical
A few crops are cold sensitive– Oriental lilies, zinnias, celosia, tropicals– Cool gradually
Storage take home: Short and cold as possibleStorage take home: Short and cold as possible
BotrytisBotrytis
Botrytis is the main problem on flowers and foliageBotrytis is the main problem on flowers and foliage Often present during production Becomes a major issue during storage and shippingBecomes a major issue during storage and shipping Try to control during production
Botrytis Development
Reducing Botrytis ProblemsReducing Botrytis Problems
Prevent condensation on the flowers!
Keep cooler and production floors dryproduction floors dry
Give breathing room inGive breathing room in buckets
Avoid mechanical damage Work clean
K fl DRY Keep flowers DRY Keep floors dry
Cut Flower HandlingCut Flower Handling
Decline due to lackDecline due to lack of water uptake St bl k d b Stems blocked by:
–Microorganisms• Bacteria and fungi naturally on plants and in tap waterand in tap water
• Build up in buckets or vase solutions
Cut Flower HandlingCut Flower Handling
Air plugsp g– Form from air drawn into xylemWhen stems cut or– When stems cut or out of water, recut to remove plug
Physiological blockage
Eventual halt of water– Eventual halt of water uptake
– No way to overcome
Sanitation Best PracticesSanitation Best Practices
Use a cleaner with a residual effect
Regularly sanitize tables, tt h dcutters, choppers, and
coolers Keep trash cans emptied p p
daily– For both botrytis and
ethylene controlethylene control
Keep hose nozzles off the floor
Minimize Cross‐contaminationMinimize Cross ContaminationMinimize Cross Contamination
High‐polluting FlowersHigh polluting Flowers
Achillea Sunflower Mums Gerbera CelosiaCelosia Dahlia ZinniaZinnia
Floral PreservativesFloral Preservatives
• Hydrating• Powders• Liquids
Hydrating• Holding• Vase
– Acidifier– Biocide Liquids
• Pills• Buckets
• Vase• Species specific
– Carbohydrate
• Jugs• Packets
specific
• Tea Bags
SummarySummary
Work clean and dryWork clean and dry Store and transport as cold as possible Use proper treatments
Harvest Time of Day
IntroductionIntroduction
M i h t• Morning harvest• Avoid heat• Higher water content• Rest of the day for processingRest of the day for processing
• Afternoon harvest• Increases carbohydrate content • Lower water contentLower water content• Decreases postharvest ethylene sensitivity
• Few studies on when to harvest cut stems for longer vase life
TreatmentsTreatments
• Harvested at three times of the day:
• Morning: 7 – 8 am• Noon: 12 – 1 pmNoon: 12 1 pm• Afternoon: 5 – 6 pm
• Postharvest performance was evaluated after either:
• No storage• No storage• 2 week storage (in water) at 35 ± 3°F
• CultivarsLi i th ‘ABC P l ’• Lisianthus ‘ABC Purple’
• Marigold ‘Double Eagle’ Gold Coin
• Zinnia ‘Deep Red’ Benary’s Giant
Vase LifeVase Life
18
141618
LisianthusMarigold
Storage Harvest time
<0.0001 0.0011
<0.0001 <0.0001
81012
se life (d
) gZinnia <0.0001 NS
246Va
07-8 am 12-1 pm 5-6 pm 7-8 am 12-1 pm 5-6 pm
No storage 2 Week StorageNo storage 2 Week Storage
Storage and harvest time
SummarySummary
Aft h t b tt th i h t f• Afternoon harvest was better than morning or noon harvest for vase life extension
• Storage reduced vase life:• Lisianthus and marigold stems harvested in afternoon had smaller reduction than morning and noon harvests
• Carbohydrates were higher in afternoon or noon harvests of lisianthus and marigold, but no clear pattern was observed for zinnia
ConclusionConclusion
Li i th d i ldLisianthus and marigold stems should be harvested in afternoon for longest vase life
Water Quality
Water QualityWater Quality
Hi h lit t t t t k•High quality water promotes water uptake•EC levels vary with species
Target pH 3.0‐4.0
Initial pH 5.0‐7.0
Vase solution pHVase solution pH
Low pH optimum for almost all
20
Low pH optimum for almost all species Tap water usually has too high of pH
12
16
e (days)
Adjust it!!
4
8
Vase life
03 6.2 7.6
l iVase solution pH
Mum ‘Naru Lavender’
Electrical conductivity (EC)
Zinnia ‘Benary’s Giant Scarlet’
Electrical conductivity (EC)
101112
Zinnia ‘Benary’s Giant Scarlet’
67890
e (day
s) With Holding
3456
Vas
e life
Without Holding
0123
0 2 30 1 2 3 4Solution EC (dS/m)
Effects and Control of Ethylene
What is Ethylene?What is Ethylene?
Natural ripening hormoneNatural ripening hormoneProduced internally in flowers and externally by hother sources
• Fruits, veggies, flowers• Mechanical damage ( i d i f(triggers production of internal ethylene)
• Exhaust from combustion enginesengines
• Cigarette smoke, BBQs, fireplaces, space heaters
• Bacteria, yeast, and fungi, y , g• Air pollution
Signs of Ethylene ExposureSigns of Ethylene Exposure
Leaf, flower and bud abscissionB d b ti
Hydrangea Lily
Bud abortionRapid flower senescencesenescenceEpinasty ‐ distinctive curling, drooping of
Waxflower
g, p gleaves or bracts
Waxflower
Minimizing Ethylene EffectsMinimizing Ethylene Effects
LLower temperatureApplying anti‐ethylene agentsRemove sources
Anti‐ethylene AgentsAnti‐ethylene Agents
STS (AVB) STS (AVB) • First solution to use immediately after harvest• Use only once on each batch of flowers• Protects for entire flower life• Protects for entire flower life• Registered in CA, WA, MN, TX• Safe disposal is a major issue
( h lbl ) 1‐MCP (Ethylbloc)• Non‐toxic gas treatment for coolers and trucks • Also available as sachets for packing boxesP i l 10 d• Protection lasts up to 10 days
• No disposal problems ‐ short re‐entry period• Not as long lasting
Water
STS
1-MCP
Postharvest Evaluation of CutPostharvest Evaluation of Cut Celosia, Eremurus, Marigold, and S dSnapdragon
TreatmentsTreatments
Expt 1: Harvest stageExpt. 1: Harvest stageExpt. 2: Harvest proceduresExpt. 3: Ethylene sensitivityExpt 4: Storage methods &Expt. 4: Storage methods & durationExpt. 5: Grower treatments (Hydrators)Expt. 6: Wholesaler treatments (Hydrator + Holding preservatives, sucrose pulses)Expt 7: Retailer/FloristExpt. 7: Retailer/Florist treatments (Vase preservatives with or without floral foam)
Celosia SummaryCelosia Summary
• Harvest at:• Harvest at:• Early stage (with only <1 in. head size) for longest vase life (10‐14 days longer)
• Later stage (>2 in. head size) for bestLater stage (>2 in. head size) for best visual quality
• Store only in water, preferably for not more than a weekmore than a week
• Place continuously in FL Clear Professional Flower Food, with or i h fwithout foam
• Celosia stems should not be:• Placed in hydrator and/or holding• Placed in hydrator and/or holding solutions
• Pulsed with sucrose
Eremurus SummaryEremurus Summary
• Harvest when no florets are open• Harvest when no florets are open
• Handle in water (‘Line Dance’) or dry (‘Tap Dance’) after harvest
• Store no more than one week• Treat with 0.2 mM STS for 4 h to overcome ethylene effect
• Pulse with 10% sucrose with 7 ppm KathonPulse with 10% sucrose with 7 ppm KathonCG, for 24 h
• Place continuously in commercial floral preservativespreservatives
• Stems should not be:• Placed in hydrator and holding solutions• Placed in floral foam
Marigold SummaryMarigold Summary
• Harvest when ≥ 50% petals have• Harvest when ≥ 50% petals have opened, for visual quality
• Stored dry, but not for more than 2 weeksweeks
• Hydrate after harvest with either STS, FL Hydraflor 100, or Chrysal Professional 1 for (4h)
• Pulse with FL Hydraflor 100 (4h)Pulse with FL Hydraflor 100 (4h) followed by FL Clear Professional Flower Food
• Place continuously in FL ClearPlace continuously in FL Clear Professional Flower Food with or without foam
• Stems should not be:Stems should not be:• Pulsed with sucrose• Placed in floral foam
Snapdragon SummarySnapdragon Summary
H t t• Harvest at:• Early stage (when lowermost floret starts expanding) for longer vase life
• Later stage (when 2‐3 florets have• Later stage (when 2‐3 florets have opened) for best visual quality
• Store dry for not more than 2 weeks• Store dry, for not more than 2 weeks• Hydrate with 0.2 mM STS (1 mL.L‐1 Chrysal AVB), or FL Hydraflor 100 for 4h
• Pulse with 5% sucrose for 24h• Pulse with 5% sucrose for 24h
• Place continuously in FL Clear Professional Fl F d Ch l Cl U i lFlower Food or Chrysal Clear Universal Flower Food without foam (foam reduced vase life)
Questions/Comments…..