With their versatility and flavour that it adds to food, onions are the star ingredient of any kitchen. They add depth and character to any dish and will bring a tear to your eye. But an onion is more than just a vegetable, it’s a secret weapon for culinary success with health benefits as well.
Onions are packed with nutrients, they are a great source of antioxidants, and they can help to boost your immune system. They are truly a superfood that should be a staple in any kitchen. And to make life even easier, you can plant your own onions to enjoy.
From dirt to dinner
According to horticultural scientist Marina Jordaan, based in Cradock in the Eastern Cape, growing onions is all about timing and location. Planting the right type of onion for your specific area, at the right time of year, is key to success.
She says onions require an ideal balance of daylight and temperature to form stunning bulbs. It’s a bit like a carefully choreographed dance, where different varieties have different needs.
“The amount of daylight needed for an onion plant to begin forming bulbs varies by variety,” Jordaan says.
With the right conditions, onions can bloom anywhere in South Africa. Short-day onions are best suited for the summer months, as they thrive in longer days and warmer weather. Intermediate onions, on the other hand, need cooler temperatures and shorter days of autumn and winter. Yellow onions, being short-day varieties, can be grown all year round in the country’s many climates, explains Jordaan.
The optimal time to plant onions
Jordaan says the yellow star/Chelsea onion is a variety of short-day onion, meaning it needs a specific number of daylight hours to produce bulbs. In South Africa, it is typically planted from February to March, to mature during the warm summer months.
It prefers loamy soil with good drainage and pH between 5.5 and 6.5. In the first few weeks, it is important to water the onions frequently to establish strong roots. After this establishment period, they should be watered at weekly intervals to produce a good yield.
To successfully grow onions, it’s important to understand the various stages of growth and their unique requirements, Jordaan explains.
The first stage is establishment when frequent watering is needed to encourage root growth. During the second stage, the bulbs are formed, and watering should be reduced to once per week. Finally, during the curing stage, watering is stopped completely for 2-3 weeks, she adds.
She points out that, when 75% of the planting’s leaves have toppled, it’s time to harvest the onions. The bulbs should then be dried (cured). When drying onions, they should be stored in single rows, with the leaves of each onion providing shade for the next.
Healthy, happy, and flavourful!
Tshwane-based plant pathologist Sibongile Jiyane explains that yellow onions have a strong flavour due to their high sulphur and quercetin content. Quercetin is a type of flavanol found in other fruits and vegetables like berries, apples, and plums. Flavonols may have antioxidant and anti-inflammatory properties, which may provide health benefits.
Different types of yellow onions have varying nutritional values, but they are generally rich in nutrients.
According to Jiyane, eating flavanol-rich fruits and vegetables is a cost-effective way to support overall health.
Caution and care
While flavanol-rich plants and fruits may have many health benefits, they could be toxic if consumed in excess, warns Jiyane. In high doses, flavanols may induce mutation and interfere with hormone metabolism, which could have serious health consequences. Therefore, caution should be exercised when consuming flavanol-containing foods such as yellow onions.
“On the other hand, onions can be a powerful home remedy for the common colds and flu.”
Jiyane recommends that, if you’re suffering from the flu, a mixture of onion, water, honey, and thyme may help. Combine chopped yellow onion, a half cup of water, a half cup of honey, and a dash of thyme in a bowl or jug and let it sit overnight. The next day, drink the mixture to help clear your airways and boost your immune system.
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