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Understanding water quality: The key to beautiful flowers

While there are many factors that affect cut flowers, water quality is one of the key factors. It might seem simple, but water can actually be quite complex. Water quality has four main factors: pH level, alkalinity, hardness and total dissolved solids. Understanding the complexity of water quality can make a difference in retailers’ success. Since flowers are a perishable commodity, that have been severed from the very root system that provides them with life, water is critical in the performance of flowers for the end consumer. Consumers that have a good experience with their flower purchases are more likely to repeat purchase. Ultimately, consumer satisfaction is good for the entire industry.

Proper pH of water
The proper pH of the water that is used for cut flowers is a determining factor in the health and longevity of your flowers. The pH scale is a numeric scale used to specify the acidity or basicity (alkalinity) of an aqueous solution.

The pH scale ranges from “0” to “14,” with a pH of 7 being neutral, a pH below 7 considered acidic and a pH above 7 considered basis or alkaline. What does the pH value tell you? A change in 1 pH unit is a tenfold change in the acidity. For example, a pH of 6 is 10 times more acidic than a pH of 7.

Typically, tap water alone will have a pH range of 5 to 8. Optimum pH is between 3 and 5, as then the uptake of solution is stimulated best, which results in keeping foliage and flowers turgid. Using flower food will ensure your water is at its optimal pH level. Flower food contains an acidifier and aims to bring the pH in the optimum range.

Importance of alkalinity
Knowing the pH of your water gives you only limited information. What’s even more important is how easily the pH changes, or its buffering capacity. The alkalinity level of your water describes its buffering capacity. A higher alkalinity means that the water contains a higher number of carbonates, bicarbonates and hydroxides, which resist the change of the pH (and potentially reducing the effectiveness of flower food).

What this means is if the alkalinity is high then it will be harder to reduce the pH to the optimum 3-5 range. Additionally, if alkalinity is too low then it may be too easy to change the pH with the acidifiers in the solution and cause the mixed solution to be too acidic (below 3pH).

Alkalinity is the most important factor when considering what the pH will be after adding flower food.

Occasionally, water will have such high alkalinity that regular flower food is not able to bring the pH down into the optimum range. In these extreme cases (usually with alkalinity much greater than 300 ppm, parts per million), a deionizing or reverse osmosis system is recommended to lower the alkalinity. Although optimum pH may not be reached if recommended dosage of flower food is applied, flower food is still effective, as stems still take up solution, but probably less than at lower alkalinity.

Hardness levels
The level of hardness refers to the amount of calcium and magnesium in your water (measured in ppm). Typically, these levels are not a good indicator of how cut flowers will react in your water. In general, most highly alkaline waters also have high hardness levels. If you have hard water, it is not recommended that you install a water softener that replaces calcium and magnesium ions with sodium ions. Sodium ions tend to be harmful for flowers at high levels.

Total dissolved solids (TDS)
The total dissolved solids (TDS) is a measure of all the dissolved solids in the water (measured in ppm). The level of TDS is important, it is essentially the level of salts in the water. Similar to humans, too much is considered bad for flowers and too little is also bad, it is always good to have a healthy balance of salts.

High levels of certain salts can potentially reduce flower life. The mixture of dissolved solids is also important. A mixture of moderate levels of calcium, magnesium, potassium and sulfates can be beneficial, while a mixture of high levels of iron, fluoride, and sodium can be harmful.

Check your water
Together, pH, alkalinity, hardness and TDS can tell you how your flowers will react to your specific water type and how effective flower food will be. It’s a good idea to check your water, and if you need help determining the quality of your water there are companies that will evaluate your water for you, such as Floralife.

Help your water
Your flowers can be improved by adding flower food to water. Flower food is a necessity, not a luxury. As soon as flowers are cut they no longer have access to water and food and are beginning to die. Flower food ensures that the flowers continue to receive food and stimulates water uptake by reducing the pH of the water. All this stimulates the development of stems, leaves, petals, size, color and scent. Flower food optimizes the vase life of flowers and improves quality.

Water temperature
The optimum water temperature for flowers is up to 5°C because it allows flowers to take up water more easily, bacteria develops slower so there are less problems of bacteria clogging vessels and it speeds up the cooling down process which slows down development of flowers, making them last longer. Tropical flowers are an exception to this and ideally, they should be stored at about 15°C.

It is a common myth that hot water can hydrate flowers and increase their shelf life. This is the furthest from the truth. Hot water can damage the cells of the cut flowers, causing discoloration.

Clean water
It seems obvious, but clean water is critical for healthy flowers. Sanitizing buckets, tools, work surfaces and coolers is not an appealing job, but must be done to encourage healthy flowers and to avoid the spread of bacteria that can cause the clogging of vessels. Bleach can be used to clean but must be thoroughly rinsed. Metal pots should not be used since the ions in the metal can give phytotoxic effects on the flowers. If metal buckets are used, it is recommended that a smaller plastic bucket be placed inside and used. Metals dissolve faster in acidic environment, which then could result in phytotoxicity.

For more information
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