Horticulture Science Lesson 55

Caring for Fresh Cut Flowers and Foliage

Interest ApproachDisplay a bunch of flowers at the front of the class. Ask the students if they know of any ways in which the life of the flowers can be extended. Record a list of ideas on a chalkboard or overhead for all to see.

Student Learning Objectives• Explain the basic requirements of cut flowers.

• Understand the causes of deterioration and death of flowers.

Student Learning Objectives• Describe the steps of effective conditioning of flowers and foliage.

• Explain the importance of using floral preservatives.

Student Learning Objectives• Examine commercial packing and shipping.

Terms• acidic• alkaline• bent necks• conditioning• ethylene inhibitors• floral preservatives• graded• hard water

Terms• hardened• precooled• respiration• salinity• senescence• soft water• transpiration• turgid

When a flower is cut, what are its needs?

• Even after fresh flowers have been removed from plants, they continue to photosynthesize, that is, they produce food from sunlight.

• Two needs for maintaining the health of cut flowers are water and sugar.

• A. The quality of water is extremely important for cut flowers.

When a flower is cut, what are its needs?

• 1. A flower is 90 percent water. – Plant cells that are filled with water are called

turgid. – As the flowers continue to photosynthesize and

respire, they will need water. – A water analysis can be conducted to determine

quality.

When a flower is cut, what are its needs?

• 2. A pH test of the water will determine whether water is acidic or alkaline. – An acidic pH has a reading below 7, and pH

readings above 7 indicate an alkaline solution. – Slightly acidic water improves water uptake. – If a floral preservative is added to water, it will

increase the acidic level, thereby increasing water uptake in plants.

When a flower is cut, what

are its needs?

When a flower is cut, what are its needs?

• 3. Water is classified as either hard water, that which contains a high level of minerals, or soft water, which has been treated to lower the mineral level.– Hard water has a high pH and is highly buffered,

meaning it is resistant to a change in pH. – Softened water has been treated with salts to

remove dissolved minerals. – The addition of salts to the water lowers the

water quality for flowers.

When a flower is cut, what are its needs?

• 4. Salinity is the measurement of the total dissolved salts in water. – Salt clogs the xylem of the floral stem,

preventing water movement, resulting in wilting and weakening of the stem.

– Salinity needs to be less than 200 ppm.

When a flower is cut, what are its needs?

• Sugars are the food source for cut flowers. • The two most common sugars are sucrose

and dextrose. • The flower gets these sugars either from

being stored in the flower tissues or through supplemental sugars provided in a floral preservative.

When a flower is cut, what are its needs?

• Fresh cut flowers require a healthy environment.

• 1. Fresh cut flowers should be placed in an environment free from ethylene gases, which cause deterioration in the flowers. – Fruit should not be stored in a floral cooler

because this causes ethylene gas exposure.

When a flower is cut, what are its needs?

• 2. Conditioning is the preparation of cut flowers and greens when they arrive at the design site. – The conditioning process involves the cutting of

stems, adequate solution uptake by the materials, and cooling.

• a. Flower stems should be re-cut and defoliated to a point that no leaves will be in the water solution.

When a flower is cut, what are its needs?

• b. Flowers are placed in water that is approximately 100 to 110°F or about the temperature of a warm bath. – Warm water speeds uptake and contains less air than cold

water. – Allow the flowers to take up water at room temperature

for several hours before placing them in a cooler.• c. Once the flowers are full of water, they can be

placed in a cooler that is 34 to 38°F. – Floral coolers are better than refrigerators because they

provide controlled humidity levels in addition to cooling. – Flowers that have been conditioned are said to be

hardened and ready for use in arranging.

When a flower is cut, what are its needs?

• Another important factor in the handling of cut flowers and greens is sanitation.– Sanitation or cleanliness improves the vase life

of flowers. – Hands, tools, knives, shears, containers and

work areas need to be kept sanitary. – Introduction of bacteria and organisms can be

avoided by cleaning work areas, coolers and containers on a regular basis.

What causes a flower to deteriorate and die?

• As soon as a flower is cut from the mother plant, it begins to deteriorate because the flower no longer has a water or food source.

• The flower will eventually die, which is referred to as senescence. – Major causes of flower deterioration and death

are determined by genetics, lack of water, time of harvest, ethylene, and disease or damage.

What causes a flower to deteriorate and die?

• The life of each flower is based on its genetics.

• The natural lives of flowers differ between species. – The flowers of the daylily live just one day. – Dutch irises live 3–5 days. – Roses have a life of 5–7 days. – Carnations last 10–14 days– Chrysanthemums live 14–21 days.

• The goal is to obtain the maximum life of each flower as allowed by nature.

What causes a flower to deteriorate and die?

• Wilting is caused by the inability of plant tissues to absorb enough water to replace water lost by transpiration. – Transpiration is the loss of water

from plant tissues. – The rate of transpiration

increases in warm environments with low humidity.

– Transpiration can be reduced by avoiding drafts and over-handling flowers.

What causes a flower to deteriorate and die?

• 1. Blocked vascular tissue can restrict the movement of water within a plant and cause wilting. – Stem blockage is the most common cause of

poor absorption.– The xylem becomes clogged and no water

movement can occur in the stem.• 2. Flowers and foliage that are fully

hydrated are said to be turgid.

What causes a flower to deteriorate and die?

• The timing of flower harvest influences flower life.

• 1. The time of day when flowers are cut is important. – Flowers should never be cut

when they are wilted. – Avoid cutting in the heat of

the day. – Evening is the best time

because plants have been making sugars throughout the day.

– Morning is the second best time to cut because plants are full of water.

What causes a flower to deteriorate and die?

• 2. The stage of flowering should be considered. – The best time to harvest is just before a flower

is fully open. – Exceptions to the rule

include the daisy and flowering bulb crops, which are harvested in bud stage, and the calla lily, which will not develop further once it is cut.

What causes a flower to deteriorate and die?

• Ethylene gas promotes senescence. – Ethylene gas is a natural plant hormone

produced by aging flowers, foliage, fruits, and vegetables.

– Common signs of ethylene exposure include large amounts of fallen petals, dropped florets, and yellowing leaves.

– Growers and wholesalers prevent this damage by using ethylene inhibitors, which are products that block or tie up the gas.

– They also strive to keep storage areas free of aging, decaying plant materials.

What causes a flower to deteriorate and die?

• Disease or damage shortens the life of floral materials. – Flowers that arrive from the market and those

picked in the garden should be of the highest quality.

– They must be inspected for disease and insect damage.

How are cut flowers and foliage conditioned to maximize vase life?

• Conditioning plant materials includes a number of steps.

• 1. Flowers should be unpacked and inspected upon receipt. – A report should be made to the wholesaler of

any problems or mistakes.• 2. Prioritize the order of processing.

– Condition the wilt-prone and expensive flowers first.

• 3. Remove sleeves, ties, and any foliage that might contact water in a container.

How are cut flowers and foliage conditioned to maximize vase life?

• 4. Under warm water, re-cut all stems, removing ½ inch to 1 inch. – Professional underwater cutting devices are

recommended.• 5. Use specific

treatment solutions as needed.

How are cut flowers and foliage conditioned to maximize vase life?

• 6. Place in a floral preservative solution mixed at the proper concentration. – Too little encourages bacterial growth while too

much can cause toxicity.• 7. Let the flowers remain at room

temperature for two to three hours to increase water uptake.

• 8. Place the flowers in a cooler set at 34 to 38°F with a high humidity level and constant light.

How are cut flowers and foliage conditioned to maximize vase life?

• Flowers with milky stems, such as poinsettias and poppies, should be treated by quickly dipping them in boiling water for five seconds and then placing them in a floral preservative solution.

• Alternative methods include exposing the cut end into a match flame without burning it or placing it in very warm floral preservative solution.

How are cut flowers and foliage conditioned to maximize vase life?

• Roses that have lost turgidity near the flower head are called bent necks.

• They can be revived by re-cutting the stems under water and placing the entire stems in a warm preservative solution.

How does a floral preservative extend the life of cut flowers?

• Floral preservatives will extend the life of cut flowers.

• A preservative contains a sugar as a supplemental food source, an acidifier to decrease the chance of stem clogging, and a bactericide to kill bacteria in a vase or stem.

• Pre-treatments are used before preservatives to reduce ethylene exposure and to hydrate flowers that are wilt prone, such as Gerbera and roses.

• All flowers can benefit from a hydrating solution treatment.

How are flowers sent from the field to the florist?

• The majority of cut flowers sold in the United States are produced in foreign countries.

• The commercial packing and shipping process affects the life span of cut flowers in the floral market.

• First, flowers are graded or separated into groups based on factors such as quality, uniformity, and size.

How are flowers sent from the field to the florist?

• They are also graded by stem quality, length, and strength.

• The flowers are then placed in bundles and sleeved for shipping.

• Delicate flowers such as Fuji mums and Gerbera are individually sleeved.

How are flowers sent from the field to the florist?

• After bundling, the flowers are boxed for shipment and precooled, a method of quickly replacing the warm air with cool air inside the box; this is also called being dry packed.

• More delicate flowers, such as snapdragons and gladioli are packed in hampers and stored in an upright position.

• The largest amount of flowers are shipped via air and then via truck to the marketplace.

Review/Summary• When a flower is cut, what are its needs?

• What causes a flower to deteriorate and die?

Review/Summary• How are cut flowers and foliage conditioned to maximize vase life?

• How does a floral preservative extend the life of cut flowers?

Review/Summary• How are flowers sent from the field to the florist?