•Choose the Right Time: Red onions are typically planted in the spring. Wait until the soil has warmed up and the threat of frost has passed before planting.
•Select Onion Sets or Seeds: You have two options for planting red onions: onion sets or seeds. Onion sets are small, dormant bulbs that are easy to plant, while seeds offer a wider variety selection.
•Prepare the Soil: Red onions prefer well-drained soil with plenty of organic matter. Choose a sunny location in your garden and work the soil to a depth of at least 6 inches. Remove any rocks, weeds, or debris, and incorporate compost or aged manure to improve soil fertility and structure.
•Planting Onion Sets: If you're using onion sets, plant them about 1 inch deep and 4-6 inches apart in rows spaced 12-18 inches apart. Press the sets gently into the soil with the pointy end facing up.
•Planting Onion Seeds: If you're planting onion seeds, sow them thinly in rows spaced 12-18 inches apart. Cover the seeds with a thin layer of soil, about ¼ to ½ inch deep, and water gently.
•Watering: Keep the soil consistently moist but not waterlogged. Onions have shallow roots and require regular watering, especially during dry periods. Water deeply once a week, providing about 1 inch of water each time.
•Thinning: If you've planted onion sets or seeds too close together, thin them once they reach about 4-6 inches tall. Leave the strongest plants and remove the weaker ones, spacing them 4-6 inches apart.
•Mulching: Apply a layer of organic mulch, such as straw or shredded leaves, around the base of the onion plants to help retain moisture, suppress weeds, and regulate soil temperature.
•Fertilizing: Onions are light feeders but benefit from a balanced fertilizer applied when they are about 4-6 inches tall. Use a fertilizer with a higher phosphorus content to promote bulb development.
•Pest and Disease Management: Keep an eye out for common onion pests such as onion thrips and onion maggots. Remove any pests by hand or use organic insecticides if necessary. Onions are relatively disease-resistant but may encounter issues such as fungal diseases in humid conditions.
•Harvesting: Red onions are typically ready for harvest when the tops start to yellow and fall over. This usually occurs about 3-4 months after planting. Gently lift the onions from the soil using a garden fork, and allow them to dry in a warm, well-ventilated area for a few days before storing.