A Comprehensive Guide to Growing Onions
Onions are a versatile and essential ingredient in many kitchens, and growing them at home is rewarding and straightforward. Whether you start from seed, transplants, or sets, onions thrive with proper care and attention. Here’s how to grow onions successfully in your garden.
Preparing the Soil
Onions prefer loose, well-drained soil that is high in fertility and slightly acidic, with a pH between 6.0 and 6.8. Before planting, enrich your soil with fully decomposed compost or manure. Avoid using cedar or redwood-based compost, as these can hinder growth. To prevent diseases like pink root or downy mildew, avoid planting onions or other alliums in the same bed for at least two years.
Planting Options
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Onions from Seed
- Start seeds indoors 10–12 weeks before transplanting.
- Sow seeds 1/2 inch deep in seed-starting mix.
- Once seedlings are 2 inches tall, feed them with diluted fish or kelp fertilizer.
- Transplant when daytime temperatures are above 50°F, spacing plants 4–6 inches apart.
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Onion Transplants
- Trim tops to 3 inches and roots to 1/4 inch before planting.
- Plant transplants 1–2 inches deep, spacing 4–6 inches apart.
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Onion Sets
- Plant sets 1 inch deep and 1–3 inches apart. Thin young plants to 3–4 inches for scallions.
Caring for Onions
Onions require consistent watering—about 1 inch per week—to prevent splitting and bitterness. Mulch to retain moisture, suppress weeds, and protect bulbs during extreme temperatures. Use phosphorus-rich fertilizers during growth for optimal bulb development.
Harvesting and Storage
Onions are ready to harvest when the tops yellow and fall over. Bend any remaining tops manually to redirect energy to the bulbs. After pulling onions, cure them in a cool, dry location until the outer skins are papery. Store pungent varieties in mesh bags or wrapped in foil for up to a year in a well-ventilated area.
Growing onions is a simple way to enjoy fresh, flavorful produce straight from your garden. With proper preparation and care, you’ll have a bountiful harvest to enhance your cooking.
