Quick Guide to Growing Onions

Before diving into the details, here's a quick overview of the essential steps for growing successful onions:

• Timing: Plant onions in early spring once the ground is workable
• Location: Choose a sunny spot with fertile, well-drained soil
• Spacing: Plant onions 6 inches apart in rows 12 inches apart
• Soil pH: Maintain soil pH between 6.0 to 6.8 for optimal growth
• Watering: Keep soil consistently moist, especially during bulb formation
• Feeding: Use continuous-release plant food for best results
• Harvest: Onions can be harvested at any size depending on your needs

Soil, Planting, and Care

Choosing the Right Variety

The sweetness of your onions depends on both genetics and growing conditions. For the mildest, sweetest onions, select varieties known for their mild flavor:

• Texas Sweet: Ideal for southern latitudes
• Walla Walla: Perfect for northern regions

Soil Requirements

Onions thrive in specific soil conditions that promote healthy bulb development:

• Sunlight: Full sun exposure for at least 6-8 hours daily
• Drainage: Well-draining soil to prevent root rot
• pH Level: Soil pH between 6.0 and 6.8
• Soil Structure: Loose, fertile soil enriched with organic matter

Soil Preparation

Proper soil preparation is crucial for onion success:

• For raised beds: Use high-quality raised bed soil mix
• For in-ground planting: Mix 3 inches of compost into the top 6 inches of soil
• Create raised rows by mounding soil, especially beneficial for heavy clay soils

Planting Technique

Follow these steps for proper onion planting:

• Plant seedlings 1 inch deep with roots well-covered
• Keep the neck of the plant at soil level to prevent rot
• Space plants 6 inches apart in furrows 12 inches apart
• Choose pencil-diameter seedlings for the largest bulbs

Ongoing Care

Consistent care throughout the growing season ensures healthy onion development:

• Watering: Maintain consistent soil moisture as onion roots are shallow and inefficient at water uptake
• Feeding: Apply continuous-release fertilizer following package directions
• Mulching: Use light, fine mulch but remove it as bulbs begin to surface

Troubleshooting

While onions are generally easy to grow, watch for these common issues:

Common Pests

• Onion Thrips: Tiny black insects that hide in leaf folds and suck plant sap
• Aphids: Small insects that cluster on leaves and stems
• Onion Root Maggots: Larvae that cause plants to wilt slowly

Prevention and Control

For specific pest control methods and organic solutions, contact your local Extension agency for region-appropriate recommendations. Early detection and proper garden hygiene help prevent most pest problems.

Harvest and Storage

Early Harvest (Green Onions)

You can begin harvesting young onions just weeks after planting:

• Harvest when plants reach desired size for scallions or spring onions
• No perfect size exists - harvest based on your culinary needs
• Plant larger seedlings close together for quick green onion harvests

Full-Size Bulb Harvest

For mature onions, timing is crucial:

• Ready Signs: Bulbs are large and tops begin yellowing and falling over
• Harvesting: Pull onions up and shake off excess soil
• Initial Curing: Lay out with tops attached in warm, airy location

Curing and Storage Process

Proper curing extends storage life significantly:

1. Cure onions for 7-10 days in dry, well-ventilated area
2. Ensure good air circulation and protection from rain
3. Allow roots to shrivel and necks to dry naturally
4. Trim tops and roots with clean pruning shears
5. Remove loose dirt without damaging papery outer skin
6. Store in cool, dry place with good ventilation

Storage Tips

• Sweet Onions: Wrap in newspaper and refrigerate for shorter-term storage
• Storage Onions: Keep in cool, dry place with good air circulation
• Avoid: Storing in plastic bags or humid conditions