What are Onions good for? Nutrition Facts and Health Effects

What are Onions good for?

What are Onions good for is a popular question. In fact, it is an old crop and occupies an important position in vegetable production in the world. There is no country, no ethnicity that does not include Onions in the daily diet. So, Garden How will provide you with all of the information about this vegetable.

What is an Onion?

What is an Onion?
An onion is also known as the bulb onion or common onion.

Scientific name: Allum cepa L.


Onions grown today are the product of human creativity. People said that Onions originated in Persia, where they first appeared in antiquity. Italians and Greeks both wrote about the Onion plant. In the Middle Ages, Onions arrived in Europe from Spain, which also carried them to North America.

During the World War, Onions contain a lot of value, General Grant sent a telegram to the Secretary of War in the summer of 1864: “I do not move troops without Onions”.

The origin of the Onion is still a matter of some enigma. Linnaeus, Don, and Regel, who wrote the Onion monograph, also failed to pinpoint its exact origin. Most botanists are hesitant about A.cepa as a wild plant.

Common Onion group: Var. cepa

Most of the important Onion varieties belong to this group. They differ in shape, stem color, response to light, and temperature.

What is the character of the Onion?

Root system

Root system
Onion plants have fibrous roots.

Belongs to the cluster root system, they have roots that are mostly in the topsoil and have a low tolerance for dryness. At a temperature of 2-3 o C, roots start to grow. The Onion root system makes up of numerous long, weakly branching fibers that are heavily coated in suckers. When uprooted, this kind of root is highly susceptible to withering. Soil that is fertile, permeable, and moist must be used for planting.

Stems and leaves

The form of the leg’s base, which is placed immediately below the false body, is the Onion’s very short and deteriorated genuine body (the tuber). There are vegetative and vegetative sprouts on the true stem, and they are encased in lush, succulent leaf sheaths (user organs).

Stems and leaves
Depending on the weather, the first Onion is a cotyledon, which appears 10-15 days after germination.

Stem tuber

It is the used part made up of many leaf sheaths.

True leaf

Depending on the weather, the first Onion is a cotyledon, which appears 10-15 days after germination. The flat, circular, and tubular Onion leaves have a waxy film covering them. Onion leaves develop relatively slowly in the early stages. Besides, they only extend a few centimeters after sprouting. Except for weeds, shoveling is a crucial task at this point. The length of the leaves depends on their ability to grow. As they age, they also begin to form tubers.

The primary organ of the Onion that is employed is the leaf sheath, which also makes up the Onion. The variety and growing method affect the number of leaf sheaths. Also, the spiral-shaped leaf sheaths are grouped on the stem in a tight spiral; the tighter the spiral, the more storage and transit space are available, and the higher the yield. Because the quantity, size, and thickness of each leaf sheath all affect the size of the tubers.

Flowers and seeds

The flower has 6 sepals, 6 stamens, and pistils, and it is the first flower. Cross-pollination occurs in flowers (pollen ripens first). As a result, it is necessary to pollinate nearby blooms or blossoms on other plants. Insects and wind both play a significant role in pollination. Gray-white flowers may turn purple or pink. The upper ovary has three compartments, the style is quite tiny, and if fully pollinated, there are six seeds.

What is the character of the Onion?
Flowering Onions offer colorful, distinctive, and long-lasting forms.

Flowering branches 60-100 mm long, tubular, green, a bunch of flowers with 250-600 flowers, flowers distributed in 3 floors. Therefore, the time and maturity between the floors are different, the flowering period lasts for months, and the inflorescences have a canopy shape.

Seeds: black, polygonal, hard shell, rough, thick, 1 gram of grains has about 250-400 seeds.

Requirements for the development condition of Onion


Because they are native to areas with varying daytime and nighttime temperatures, Onions are plants that prefer cold climes, have a very wide range of temperature tolerance, and can withstand both cold and hot temperatures. great. The ideal temperature range for Onion growth and development is between 16 and 20 °C. However, this range fluctuates according to the plant’s stage of development.

At a temperature of 20–22 o C, Onion seeds begin to germinate at 2-3 o C with soil moisture of 80–90%. The ideal temperature for growing plants (from seeds) is 22 to 25oC, while charcoal grows best at 18oC. When temperatures are high, 30-32oC, plants grow quickly at first but then slow down. Onions tolerate low temperatures quite well, while mature trees are more resistant to cold than young ones and can withstand -7oC.


It is a light-loving plant that prefers long days, with differences between varieties, and can divide into two groups:

  • Short-day variety, 10–12 hours of short-light conditions for tuber production, and no tuber formation while upright. These types are early ripening cultivars.
  • Varieties with long days form tubers when there are more than 15 hours of light per day; no tuber formation occurs between 10 and 12 hours per day. The lighting period ranges from 12 to 16 hours each day, and this improves plant operations.

With only eight hours of light per day, plants make less vitamin C, grow more leaves, take longer to mature, and do not produce tubers.

The number of leaves grows and the plant takes on a dusty appearance as a result of the short light, high temperature, and big nutritional area stimulating leafing on the tree.


Onion seeds contain many angles and thick shells, making it difficult for water to reach the seeds when they are germination. As a result, Onions require a lot of water. Because Onion roots are fragile, they cannot withstand drought. As a result, consistent moisture in the soil is necessary from the time of germination until the plant has 4-5 genuine leaves.

The tubers are little and the leaves expand when it rains. Watering is a crucial technological strategy to boost Onion yield in regions with strong radiation, high evaporation, and low rainfall. The amount of water used to produce one tonne of Onions is between 50 and 70 m3, claims Xoboleba OM. In the growth period, humidity ranges from 70 to 80%, not 45 to 55%, and unhealthy plants are not grown there. Low humidity has a substantial impact on tuber form and harvest time in arid places where humidity is difficult to regulate because the root system dries out and dies. The Onion plant’s huge, swelling neck from too much water will prevent it from becoming ripe, old, and dry.


The ideal soil for growing Onions is one that is light and rich in organic matter. Growing Onions in a mixture of sandy and loamy soil frequently results in large yields. A suitable supply of nutrients will be provided by fertile soil for Onion plants to grow and thrive. 

Although the output is more minor and Onions ripen quicker than in soil, the mixed sand still offers necessary nutrients. Young Onions are fragile and should be planted in soil that is small and free of rocks. Dry and well-drained soil is ideal.

Onions can tolerate slightly acidic soil, but a pH of 6.0-6.8 shows well with an adequate supply of nutrients. 

If the pH is below 6, the plant will be sensitive to acidic soil, leading to reduced yield and reduced quality. Onion plants can also grow at a pH of 7.5-7.8 on soils rich in key nutrients.

What are Onions good for?

Onion is a widely used plant. People use Onions to cook soup, boil, bake, make ice cream, and salads,… The daily amount is not much, but for the whole year, the amount is considerable. Besides, Onion has high economic value. It contains 12% of dry matter; 6.5% total sugar; 8.9% vitamin C and 1.8% crude protein.

Tolerance to late blight is medium.
Onion has high economic value.

The area and yield of Onions in the world are constantly increasing over time. The area under Onion cultivation in Asia is the largest. However, the leading country in terms of area is the US, in terms of output is China and in terms of productivity is the Soviet Union. 

Also, Onions are an important export item for many countries around the world. In our country Onion is a crucial winter crop in many regions, growing Onions brings higher economic efficiency than other crops such as rice, melon, and corn,…

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What are Onions good for?

Using Onions in medicine

Onions are not only widely used as food but also as valuable medicine. Onions contain many antibacterial substances. Especially the phenoxide. Besides, Onions cure many diseases and stimulate the activity of the heart, and kidneys. People use Onions to treat eye diseases, ear infections, and arthritis. 

Besides, Onion juice with honey can reduce cough, fresh Onion juice can treat intestinal diseases. They have the effect of treating blood pressure and arteriosclerosis. 

Some popular Onion varieties

Japanese F1 Granex Onion variety

This variety is widely grown in Onion-growing areas. The variety has a growth period of 130-140 days. The tubers are round and flattened, with a diameter of 8.5 cm, the average weight of the tubers is 265.5 g, and the average yield is 20-25 tons/ha. Good quality, delicious, and sweet. Tolerance to late blight is medium.

Japanese F1 Grano Onion variety

The variety has a growth period of 130-135 days. The average yield is 15-20 tons/ha, the tuber is spherical, the spacing between the leaves is considerable, the sheath is thick, the diameter of the tuber ranges from 6-7 cm, and the average weight of the tuber is 150-200 g. Good quality has a less offensive odor and is delicious to consume. moderate disease resistance.

In the delta, Onions do not now blossom, thus seeds must be imported. This presents a challenge for the growth of the Onion-growing regions in our nation. Recently, Chinese Onion seeds have been utilized in various parts of our country’s northern province. On the market are commercial goods made in China.

Final Thoughts

In nutshell, Garden How provided you with all of the useful information about what are Onions good for. In fact, they contain organic sulfur compounds. These compounds are the reason why Onions have such a sharp, strong taste and smell. However, they are a nutrient-dense food, meaning that they are high in vitamins, minerals, and antioxidants while being low in calories. Hopefully, this post can help you have more knowledge about this special vegetable. Visit gardenhow.net to learn more about flowers and vegetables. Thank you for taking the time to read this!

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