Red onions are a popular variety of onions known for their vibrant red or purple outer skin and mild, sweet flavor. They are widely used in various culinary dishes and can be enjoyed both raw and cooked. Red onions add a beautiful color and a subtle sweetness to salads, sandwiches, salsas, and other savory dishes.
Botanical name: Allium cepa
Plant morphology: Red onions have a bulbous shape with multiple layers of reddish-purple or deep red skin. The inner flesh is crisp, white, and often has red streaks. The leaves of the onion plant are long and slender, and the plant can reach a height of about 30-45 cm. When left to mature, red onions produce spherical flower heads with small, white or pink flowers.
Soil and Climatic requirements: Red onions prefer well-drained soil with a pH level between 6.0 and 7.0. They can tolerate various soil types but thrive best in fertile, loamy soil. They require full sun exposure and can grow in a wide range of climates, but they generally prefer cooler temperatures.
Crop Duration: 90-120 days
Cropping season: Red onions are typically planted in early spring or late summer to early fall, depending on the climate. They require a longer growing season compared to some other onion varieties.
Planting type: Direct sowing or transplanting.
Spacing: Plant red onion bulbs about 3-6" apart in rows that are 8-14" apart.
Depth of planting: Plant the bulbs with the pointed end facing upward, and bury them about 1-2 cm deep in the soil.
Germination period: Red onions usually take around 6-16 days to germinate.
Hours of sunlight required: Red onions require full sun exposure, ideally 8-10 hours of direct sunlight per day.
Watering: Keep the soil consistently moist, especially during the early stages of growth. Avoid overwatering to prevent waterlogging.
Harvesting: Red onions can be harvested when the tops start to fall over and dry out. Once the foliage has dried, carefully lift the bulbs from the soil and allow them to cure in a cool, dry, and well-ventilated area for a few weeks. The outer skin will become papery and the flavors will intensify during this curing process.
Companion plants: Carrots, lettuce, beets, and herbs like basil and chamomile.
Problems of Red onion cultivation:
Pests: Onion maggots, thrips, onion flies, and aphids.
Diseases: Downy mildew, pink root disease, and botrytis leaf blight.
