Beware of the Silent Flower Killer

Ethylene, an odorless and colorless gas, is deadly to many cut flowers and potted plants. Here’s everything you need to know to protect your flowers and plants.

By American Floral Endowment

Ever heard of ethylene? No doubt, many of you have, but for those who haven’t, it’s the silent killer of flowers, and it saps profits. The more you know about ethylene and how it affects the life of many flowers, the more you can do to prevent it and prolong the beauty of your blooms. Understanding the fundamentals of ethylene will improve your bottom line and ensure that your customers are satisfied with the flowers and plants from your shop.

What is ethylene?

There are many gases that affect the longevity, appearance and performance of fresh cut flowers and potted flowering and foliage plants. The most damaging gas—ethylene—is odorless and colorless. Ethylene is often referred to as the ‘’wound hormone” because it is produced naturally by plants and flowers when they are stressed by elevated temperatures or vibration during transport. Fruits and vegetables also produce ethylene as they ripen, and ethylene is often used commercially to hasten the ripening process. Ethylene is also a byproduct of combustible engines such as gasoline-powered vehicles, propane-powered floor buffers and lawnmowers. No matter the source, ethylene is equally damaging to flowers and plants.

How can one test for ethylene?

Ethylene gas in the air can be measured. Gas samples can be taken in retail and wholesale florists’ coolers and design/display rooms and in mass-market distribution centers. These measurements must be analyzed using a sophisticated gas analysis machine because ethylene may be harmful at concentrations as low as 100 parts per billion. These measurements reflect only atmospheric ethylene and cannot detect ethylene produced within flowers and plants themselves.

What are the symptoms of ethylene damage?

Ethylene symptoms vary depending on flower and plant type and variety. The most common responses to ethylene are reduced vase life, bud and petal drop, leaf abscission and failure of flowers to open (Figure 1). The sidebar on Page 00 lists of some commonly known flowers and plants that are sensitive to ethylene. It is also important to note that some flowers and plants are not particularly sensitive to ethylene.

How can you protect flowers from ethylene damage?

There is good news. Several companies such as FloraLife and Chrysal have developed postharvest products that are proved to protect flowers from the detrimental effects of ethylene. For example, roses treated with FloraLife^® EthylBloc^™ open and last longer than nontreated flowers (Figure 2). Ethylene is equally harmful to potted plants, such as Kalanchoe (Figure 3).

FloraLife’s EthylBloc^™ Technology is 1-MCP based and is formulated to treat both cut flowers and potted plants, but the company also offers EthylGuard 100, an STS-based liquid for cut flowers only. Chrysal has two anti-ethylene products: Chrysal Ethylene Buster^® (1-MCP based, for both cut flowers and potted plants) and Chrysal AVB (STS based, for cut flowers only). STS (silver thiosulfate)-based products require special care in disposal.

Buy only from growers and shippers that treat flowers and plants with an anti-ethylene product. These products not only protect against damage from atmospheric ethylene but also prevent the internal production of ethylene.

It is best to have flowers and plants treated by the growers, so they are protected during transport, storage and display (Figures 2 and 3). So, ask for it! In this way, stress encountered during shipping and handling periods will not cause the internal production of ethylene. Also, cut flowers and potted plants are protected from ethylene in trucks and coolers throughout their entire journey from grower to consumer. Pretreatment with these products prevents the need for air purification in coolers. Also, air purification systems in coolers may prevent damage from atmospheric ethylene, but they have no effect on internally produced ethylene.

Why is it important to keep flowers cold?

One of the most important reasons for keeping flowers cold is that ethylene is much less harmful at lower temperatures. Research has demonstrated that ethylene affects plants less if they are cold. But we will skip all the numbers and just emphasize that flowers last longer in cold-temperature storage partly because they are more resistant to ethylene at lower temperatures.

Ethylene can kill your flowers, but it doesn’t have to kill your profits. Take ethylene exposure seriously, and look for suppliers who monitor and treat for ethylene at every step along the supply chain.

STILL HAVE QUESTIONS? Email us at afe@endowment.org. We’ll follow up in an upcoming issue to answer more specific questions about ethylene.