Harvesting and Handling Cut Flowers

In Cameroon Highland, a lot of farm and garden growers propagate cut flowers to be sold in garden centers, stands on the roadside, markets, and farm shares. To ensure a high-grade product and make the most out of the flower’s vase life, proper cultivation and maintenance of flowers after harvest is crucial. Below are a few tips for the appropriate cultivation and maintenance of cut flowers.

The shelf life of newly-cut flowers relies on pre-cultivation procedures too. To have the best cultivars for cutting, before cultivation, the cultivar selection should be accounted for longer after harvest life.

Weather is to be considered for it can also have an impact on the after-harvest life of flowers. For instance, soil can be weathered on plant stems with heavy rainfall. This could mean a vast chance for germs and bacteria to contaminate and might block stems after its harvest. Also, plants should not be stressed due to overwatering before harvest. They need to be of great health and watered properly before cutting them. This makes their cell walls rigid.

 

The appropriate stage to harvest flowers

To be confident about the quality of the flowers after harvest, one should identify the optimal stage of cultivating each type of plant. For the shelf life of the freshly cut flowers to be maximized, flowers need to be harvested every day at their appropriate phase of growth.

Having it a little early or a little late can have serious effects on the vase longevity. Once cultivated after the optimal stage, carbohydrates are utilized by growing flowers for the growth of smaller buds. This results in the slowing down of the development of the others.

Every plant has a required cultivation phase (mostly minimum) wherein flowers are harvested without damaging their value after harvest. There are some flowers however that is cultivated right at their early phase without sacrificing their quality and their shelf life.

For others, matters like the bent neck, inappropriate progress of the pigmentation process or the unusual opening of the buds, may arise if flowers are cultivated even if they are still undeveloped. Normally, flowers are harvested at their early stage if stockpiled and transported in long distances.

 

Tips for Harvesting:

• For Spiky flowers, the best time to reap them is when one-fourth to one-half of the florets are opened.
• For the Daisy type, the best time to harvest them is once they are fully opened.

 

Before Harvest:

• Plants must be in good physical shape.
• Cutting tools and plastic buckets (preferably white) are to be disinfected and washed. Stacking the buckets should not be done if they are not clean both inside and outside.
• Sharp cutting tools is an edge. You do not want crushed stems. It may reduce the plant’s water intake.

Cleaning and disinfecting the buckets must be done habitually. Bacteria are harbored in the dirt, which may clog the flowers’ stems. Washing the buckets with low-suds and biodegradable detergent, then rinsing it with water, before giving it a final rinse with a solution containing 1mL Clorox (5% hypochlorite) per liter of water is necessary.

Dirt on white buckets is way noticeable than the dark-colored ones. Also, clean water must be placed inside harvesting buckets. Other growers put fused water with a biocide. Biocides are known to stop the mutation of microorganisms.

The good thing is biocides are available in the market. Microbes and other substances that are produced contribute to the blocking of water uptake. They block the plant’s xylem. It is proven through research that the level of microorganisms that are present in the water and the longevity of the harvested flowers have a solidly conflicting relationship.

Bleach, aluminum sulfate, and salts of 8-hydroxyquinoline are some biocides that are commonly used by growers. Household bleach, however, has a short life span compared to the commercially usable chlorine tablets.

Farmers use chlorine tablets and dilute it in water during cultivation. Instructions and the company’s reference to the proper dilution amount for biocide must be followed. Also, it varies among species of flowers.

Also, the pH level of the water must be around 3.0 to 5.5. So, water has to be acidified. Demonstrations from researchers have illustrated that water is more absorbed by the flower if it is acidic than those with high pH levels. Aluminum sulfate, citric acid, or 8-hydroxyquinoline citrate is usually utilized to lessen the pH of the water.

The required quantity of the chemical is dependent on the water’s alkalinity. The measurement of the calcium and magnesium carbonates that are present in water is referred to as its alkalinity. High alkaline levels in water are highly secured thus require more chemical quantity to control the pH level.

An analysis of the water’s pH level and alkalinity should be done to identify the amount of solution needed to regulate the pH to a desired state. Water sampling and testing is available in laboratories, both public and private. With elevated levels of sodium, fluorine, or sulfate, water can become toxic.

 

Post Harvest Care of Organic Flowers

You might skip preservatives and biocides because they are not approved for organic growing. Organic farmers are recommended to seek advice from their certifying agents. Approved organic flower farmers are the ones that practice first-rate hygiene and harvest during the appropriate phase of development to make sure the flower’s shelf life is maximized.

Harvesting

• It is best to harvest either during mornings or evenings.
• Stem foliage below the water level must be removed.
• In cutting the stems, cut it slant-wise for it will prevent the stems flatly lying at the bottom. Thus, increasing its water uptake.
• Laying flowers on clean ground or surface is a no-no.
• Cutting tools must be disinfected regularly, at least twice a day.
• After harvest, immediately grade and bunch the cultivated flowers.
• With a bucket of warm and clean water and biocide, place the water inside the bucket and bring them to shade.
• Filling the containers with too much water is not allowed.

As mentioned, flowers are best harvested during early morning or evenings and not in the middle of a scorching afternoon. It is ideal for them to be harvested when the temperature is low and the water content of the plant is great. Cuts have to be made to maintain its lengthy and robust stems.

Foliage will rot and it encourages microbial growth so it should be disposed of. An example is the Sunflower, their foliage is entirely removed. For some flowers, main stem shoots are detached during cultivation. Cutting the stem in slant, on the other hand, will benefit the plant in its water uptake.

Before placing the flowers in the water, grading and bunching must be done. This reduces injuries that occur often on the flowers and its leaves. When forgotten to do so, the flowers must be submerged in buckets with warm water and biocide immediately. Over-crowding of containers should be avoided to prevent them from bruises and tangles.

While in harvest, buckets should be prepared at each end of the row. Flowers must be placed here after being freshly cut. This is to avoid placing them on an unclean surface where the chances of bacterial contamination are relatively high. Disinfection of cutting tools must be done frequently, if not regularly.

Harvesting in small quantities is ideal and once done, place the flowers in a shady area in their buckets. The shady area helps with the regulation of the temperature, reduction of the loss of water, and stabilizes the respiration rate of the flowers. This will improve the flower’s life.

          

Tips to do after harvest

• Place the flowers in cool areas.
• While underwater, give the stem another cut
• Transfer the flowers in a solution according to their need.

Once the harvesting is done, flowers are placed in cool areas where they are given another cut and moved in a solution according to their need. Flowers will remain to transpire but most of them recover once contained in a warm rehydrating solution. Re-cut the stems an inch before setting them in the solution.

 

How important temperature and humidity?

The management of the temperature is a crucial aspect of keeping the quality of the flower’s shelf life. As its storing temperature goes high, wilting happens. Cooling the cultivated flowers is done to decrease heat.

In the name of convenience, flowers can be displayed outdoors if they are sold within that day. For the market, they must be placed in a cooler immediately with temperatures (in Fahrenheit) close to 33 (a majority of flowers), and 41 to 43 (for flowers like zinnia and gerbera) or 50 (cold-sensitive flowers) to preserve its value.

Usually, lowering the temperatures will make the flowers live longer. If temperatures are close to freezing point (33 F), most flowers preserve their value. Flowers from the tropical and subtropical countries may develop chilling injuries if kept at below 50 ℉ temperatures.

The relative humidity is also a separate factor because it affects the solution intake. Relatively high humidity helps reduce transpiration and keeps the flowers fresh.

 

Improving Water Quality

Water and buckets should always be clean and sterilized regularly. Replacing the solution usually decreases the chances of microbes in the water, which causes the water to appear blur and cloudy, thus preventing bacterial contamination in the stems for better water uptake.

Particular ions in the water are also a factor. The quality of water that is considerable for human intake is not advisable for flowers. For instance, fluoride is not good to flowers like gerbera, gladiolus, and freesia. Sodium and iron are also not good to some flowers, at great levels, and should be avoided.

 

Supplying food

Newly-cut flowers must be placed in normally dark or low light environments where food production and respiration are minimal. Photosynthesis, the process of food production in plants, is slow in areas with less sunlight. Food or commonly known as carbohydrates are utilized by the cut flowers for its continuing growth.

Aside from using the uncontaminated water added with biocide, a constant food supply is vital for flowers for a maximized life after harvest. Adding preservatives in the solution can help in achieving the best growth of many flowers. Other rudimentary flower care products are comprised of:

• Anti-ethylene treatments
• Hydration solutions
• Specialized solutions
• Holding solutions

The hydrating mixture is often warm solutions with biocide and primarily used to aid the water uptake of flowers. Also, they are used right after harvest but only for a short duration. Other growers use these solutions to stop wilting and eventually restoring flowers. To achieve pH levels of 3.5 up to 5.0, biocide and citric acid are added to the water.

Holding mixtures contain carbohydrates to help the bud to open and extend the flower’s life. They are usually utilized after the hydrating mixture and can go for a couple of hours to about two days. The concentration of preservatives differs depending on the usage. Some solutions are acidic. Some only contain a small amount.

Vase mixtures (commonly known as flower preservatives) are containing higher carbohydrate content compared to holding solutions. In the absence of any preserving agent, uncontaminated water in a sanitized bucket should be the appropriate alternative.

The inclusion of biocide is another way of escalating after-harvest care. In a gallon of water, you can add a ¾ teaspoon of bleach to increase the acidity level of the water from 3.5 to 5.0 pH. Before putting the cut flowers, it is best to test the acidity level of the water by putting fewer stems. This is to avoid harming other flowers for some might have phytotoxicity after being placed in the acidified solution.

 

Some Flowers under Postharvest mixtures

After harvest solutions vary across flower species. A research illustrated that the sparkling burgundy reached its longest shelf life by only using plain water. But, after a holding solution was added, its life decreased from 43 days to 34 days. The use of a hydrating solution reduced its life to 19 days. When both solutions were added the flower only lived for 11 days.

About 14 sunflowers were also put to test. Almost all reached a shelf life of 8 to 11 days using floral preservatives. Sunny, Terra Cotta, and Sunbright cultivars persisted for 14 days. Solara, Sunrich Orange, and Premium Lemon lasted for 10 to 12 days while placed first in a hydrating mixture, then to a holding solution.

Treatments have not made any change in the study as limelight hydrangea lived for an average of 11 days. ABC lavender was applied with both holding and hydrator mixture and it persisted for 14 to 16 days. Shortest shelf life with only water as its treatment lasted for 5 days.

 

Ethylene

It is an organic growth hormone, which is colorless and odorless. This gas aids the aging process in plants and is produced by maturing vegetables and fruits. Other sources of ethylene gas are industrial smoke, exhaust fumes, and microorganisms. To ensure a maximized life, never put flowers close to vegetables and fruits.

Some flowers are delicate to even just small amounts of ethylene. It can be destructive for them. Ethylene exposure may result in abscission, irregular growth of flower buds, and its failure to open that can lead to the eventual death of the flower.

Aside from cut flowers, cut herbs like mint, parsley, marjoram, and oregano are sensitive too. Symptoms of abscission and leaf yellowing are noticed when exposed to the gas.

The common treatment of ethylene exposed flowers includes STS or Silver Thiosulfate and 1-Methycyclopropane (1-MCP).

 

Straight Stem Maintenance

Geotropism is an occurrence wherein flower stems bend away from the gravitational pull. Curved stems are evident once flowers are positioned vertically. To correct this, the flowers should be positioned upright.

 

Physical Damage

Physical damage destroys the beauty of the flowers and leaves. Bruised petals and leaves are also more susceptible to infection. That is why the gentle handling of flowers is very important.

 

Botrytis

It is a fungal disease that can cause the flowers to discolor and decay. Its spore germination is dependent on a wide range of temperature and relative humidity. To manage this, avoid the storing and harvesting of wet flowers. In addition, let the droplets evaporate before moving the flower from a cool to warm environment. Relative humidity increases the risk of botrytis infection.