Origin Of Onion
Onion is an annual crop that can be grown and harvested within five to six months after planting. It is botanically known as Allium Cepa and is commonly referred to as bulb onion or onion. It is a widely cultivated vegetable of the genus allium; its close relatives include garlic, scallion, shallot, leek, etc.
Onion has a spicy flavor and medicinal properties. It varies in size, color, and shape; white, red, and yellow onions are the most common type. The taste of this vegetable can range from sharp, spicy, and savory, often depending on the season in which people grow and consume it.
Many food historians and botanists believed onions began in central Asia, while other researchers suggested that they originated in Iran and West Pakistan. Onions were an early crop because they were less perishable, easily grown in various soils and climates, and easy to transport.
Nutrient Composition Of Onion
Onions consist mostly of water, carbs, and fiber. Vitamin C, folate, and potassium are also nutrients found in onions. Raw onions are very low in calories, with only 40 calories per 100 grams. A 100 gram of raw onions contains the following nutrients.
- Calories: 40
- Water: 89%
- Total Protein: 1.1 grams
- Total Carbohydrate: 9.3 grams
- Sugar: 4.2 grams
- Fiber: 1.7 grams
- Total Fat: 0.1 grams
Preferred Botanical name: Allium cepa
Preferred Common Name: Onion
Local common names;
- Ibibio: Ayim
- Yoruba: Alubosa
International common names;
- English: Onion
- French: Oignon
Medicinal Properties And Uses Of Onion
- Onion is a good source of vitamin C, B, and potassium; it is low in calories.
- Onions help reduce the risk of heart disease such as high blood pressure etc.
- Red onions are rich in antioxidants that help protect against cancer and diabetes.
- It helps to reduce blood sugar levels.
- It helps to improve bone mineral density.
- It helps to boost digestive health, and it is easy to add to a diet
How To Grow Onions
Yield Information Of onion
Onions are cool-season plants. They have three distinct growth phases: vegetative, bulbing, and blooming (bolting), and environmental factors trigger the switch from one stage to the next. It does not work to plant onions at a random date in the year without taking account of these environmental factors.
Maturity of onions occurs five months after planting. Onion is a high-yield crop. Square feet of space can contain 20 to 50 onions. One stand of onion produces one onion, although there may be attachments of two onions, usually smaller in size.
Nursery And Transplant Requirements Of Onions
Onion seeds are sown on nursery beds to raise seedlings for transplanting in the field. Raised beds are used, and distances are kept to allow space for watering. The surface of beds should be smooth and well leveled because they mature much faster (and are less work overall).
It is ideal for growing onions from onion sets (i.e., small onion bulbs) rather than seeds. Once planted, they develop into a full-size bulb after about 3-½ months. Raised beds or rows at least 4 inches high are ideal for planting onions.
If planting from seeds, start them on raised beds about six weeks before you plan to transplant them to the garden. Always plant fresh seeds each year. For onion seeds to germinate well, a temperature of 50°F (10°C) is required.
You can transplant seedlings 4 to 6 weeks after planting. Slowly reduce watering and remove the shade to enable the plant to adapt to strong sunshine. It is best to transplant the seedlings early (6-10 am) or late in the afternoon (4-6 pm).
Water the plant two hours before transplanting so that you can remove each seedling with a little lump of soil. Start with strong and healthy seedlings. Weak seedlings can stay longer in the nursery so they can grow stronger.
Soil And Sun Requirements Of Onion
Sandy loams to heavy clay are suitable for planting onions. If your soil is heavy, you can introduce some organic compost or manure into the ground to help its moisture-retaining properties. Onions prefer slightly acidic soil with a pH between 5.5-6.5.
Your planting site should be where there is the full sun so that other plants will not shade your plant. Loose, well-drained, and soil rich in nitrogen is suitable for planting onions. Compacted, rocky, or clay soil hinder bulb growth.
Onions require sufficient nutrients to produce big bulbs. Nitrogen is the nutrient needed in the greatest quantities to maximize growth and yield. Calcium is also needed in relatively large amounts.
Watering Requirement Of onions
Onion plants do not require frequent watering if mulch is used. Around one inch of water (including rainwater) weekly is enough for an onion plant. Ensure to water your onions plant during prolonged dryness. Water plants in the morning or evening.
Watering in the afternoon will cause evaporation to occur. Use a hose or sprinkler to water. About 350 to 550 mm of water is required for optimum yield.
Planting And Spacing Requirements Of Onion
When transplanting into the garden, the recommended spacing for planting onions sets is 4 to 6 inches apart in rows. The planting depth should not be more than 1 inch, and the sets should be bulbs about ½ inch in diameter as larger sets may first go to seeds before producing decent size-bulbs.
Sets with smaller bulbs may not grow well. The pointy end of the bulbs is planted up, while the rounded end is the rooting end. Give plants enough space to grow well, and the yield can increase. Plant sets 12 to 18 inches between rows.
Harvesting Of Onion
A matured onion plant will stop new growth from the center when bulbs start forming. Leaves will begin to yellow and fall over when the bulbs are ripe. After three quarters, when the tops have fallen over, bend the back of the remaining tops horizontally with the back of a rake.
The plant diverts its energy to the bulbs because of the bent leaves. After the tops turn brown in a day or two, lift the bulbs with a garden fork on a sunny day, and leave them to dry in the sun. When outer bulb skins are dry, the tops wither in about a week. Wipe off any soil and cut away the tops.
Dry the onions in an airy place and toss any onions that show decay or damage signs as they can affect healthy onions if they are stored together.
Storage Of Onion
After harvesting, if the weather is favorable, allow the onions to cure on dry ground for some days. After allowing them to dry, store them in a root cellar or any other storage area. Spread them out on an open screen off the ground to dry. Ensure that no bruises occur to them because they can rot quickly.
Store at 40 to 50°F (4 to 10°C) with the stems removed in a mesh bag or nylon stocking. Keep mature and dry-skinned bulbs in a cool and dry place. Pungent onions store longer than sweet onions. You can save the pungent onions for later use while you eat the sweet ones immediately.
It is not advisable to store onions together with potatoes, pears, or apples. These fruits produce ethylene gas that interrupts the onion’s dormancy. The flavor of these fruits may be spoilt. Properly stored onions can last for 10 to 12 months. Store them in a dark and cool area (35 to 40 degrees F) like a cellar, garage, or shed to retain their quality.
Storage Of Onion Seedling
Onion sets for the next planting season are preserved the same way the bulbs are preserved. Avoid punctures or wounds and store them in a cool, dry place; this will retain their quality for a few months, and you can plant them in the next season.
Pests And Diseases Of Onion
The following are pests and diseases that affect onions.
Onion Maggots
Onion maggots are insects that affect the onion plants during rainy periods. They often lay eggs at the bottom of the plant. The following are ways to prevent the insect from attacking your plants.
- Use a fine mesh net to cover your growing onion plants.
- Mound the edges with soil to seal it.
- Keep mulch away from the onion plant because of maggots like organic matter.
- Harvest your onions when it is due.
Onion Fly
Onion flies are common in dry soils in midsummer. The symptoms are drooping yellow leaves; tender plants will not survive while older plants will be underdeveloped; white maggots inside the bulbs.
You can control it by lifting and burning affected plants. Grow from seeds if you have a problem growing from sets.
White Rot
White rot is a severe disease that affects the onion plants because its spores will remain in the soil for up to seven years. Signs include yellow and wilted plants and white mold on the bottom (after pulling the plant).
Avoid the disease by sticking to a crop rotation plant; do not transfer soil planting materials between sites. Before planting, treat seeds with hot water.
Onion yellow dwarf
A virus causes it, and symptoms include yellow streaks on the bases of the first leaves; leaves may be flattened or crinkled; undersized bulbs. You can control culturally by removing infected plants and planting more tolerant varieties.
Bulb Mites
It is caused by a pest called arachnid, which causes stunted plant growth and reduced stand and bulbs rotting in the ground. It is controlled by practicing crop rotation and allowing the field to fallow to ensure that residual organic matter decomposes completely.
Conclusion
Onions are not just vegetables – they pack a powerful punch when it comes to promoting good health. From their abundance of antioxidants, with a special mention to the potent quercetin that bolsters immune function and battles inflammation, to their cardiovascular benefits thanks to sulfur compounds that decrease blood clotting and enhance blood vessel performance, the health advantages of onions are truly vast.
Did you know that onions are not only packed with flavor, but also loaded with beneficial nutrients? Not only do they contain vitamins C and B6 which promote skin health and aid in neurotransmitter production, but their prebiotic fibers also support gut health by fostering beneficial bacteria. And the best part? These nutrient-packed goodies come in a low-calorie package and can be used in a variety of delicious dishes, making them a valuable addition to any balanced diet for overall well-being.