How to Grow Onions at Home
Onions are the heart of countless savory recipes—from sizzling stir-fries to soul-warming stews. But beyond the kitchen, they’re also one of the easiest vegetables to grow in your home garden. Whether you have a backyard bed, a raised container, or even a few pots on your balcony, onions are low-maintenance, space-efficient, and rewarding.
In this complete guide, we’ll walk you through the best practices to grow onions at home, including selecting the right variety, planting techniques, maintenance tips, harvesting, and storing for long-term use.
🌱 Why Grow Onions in Your Garden?
Still buying onions from the grocery store? Here’s why it’s time to go homegrown:
Superior taste and freshness
Control over chemicals and pesticides
Access to unique heirloom or organic varieties
Cost savings over time
Sustainable gardening and self-reliance
Homegrown onions have richer flavor and better nutritional value, especially when harvested and consumed fresh.
🧅 Understanding Onion Varieties
Choosing the right variety is critical for success. Onions fall into three main types based on their growing day length:
1. Short-Day Onions
Require 10–12 hours of daylight to form bulbs
Best for southern U.S. states (USDA Zones 7–10)
Examples: Texas Sweet, Red Creole, Yellow Granex
2. Long-Day Onions
Need 14–16 hours of daylight
Ideal for northern U.S. states (Zones 4–6)
Examples: Walla Walla, Yellow Sweet Spanish, Red Zeppelin
3. Intermediate-Day Onions
Thrive in mid-latitudes (Zones 5–7)
Examples: Candy, Red Candy Apple, Sierra Blanca
✅ Pro Tip: Match the onion type to your climate for best bulb formation and yield.
📦 Onion Growing Methods: Seeds, Sets, or Transplants?
You can grow onions using three methods:
🌱 1. Seeds
Cheapest option
Longer growing period (start indoors 8–12 weeks before transplanting)
Great for heirloom or organic growers
🧄 2. Sets
Small immature bulbs, easy to plant
Ideal for beginners
Quicker to mature but may bolt (flower) early
🌿 3. Transplants
Pre-started seedlings sold in bunches
Good balance of speed and reliability
Beginner’s choice: Start with sets or transplants for faster and easier results.
🌿 Best Soil and Location for Onions
🧪 Soil Requirements:
Loose, well-drained loamy soil
pH: 6.0–6.8
Enriched with compost or aged manure
Avoid waterlogging; onions hate soggy soil
☀️ Light:
Full sun is essential – at least 6–8 hours a day
🌾 Spacing:
Bulb onions: 4–6 inches apart
Green onions/scallions: 2 inches apart
Onions are shallow-rooted, so consistent moisture and weed control are important.
🌼 When and How to Plant Onions
📅 When to Plant
Short-day onions: Plant in fall or late winter (Zones 7–10)
Long-day onions: Plant in early spring (Zones 4–6)
Intermediate-day onions: Late winter to early spring (Zones 5–7)
🚜 How to Plant
Prepare rows or containers with 4–6 inches depth of rich, loose soil.
Place onion sets or transplants just deep enough to cover the roots (about 1 inch).
Space rows 12–18 inches apart for proper air circulation.
Water lightly after planting.
Container Tip: Use grow bags or large pots (12+ inches deep) with good drainage.
💧 Watering and Feeding Onions
💦 Watering
Onions need consistent moisture (1 inch/week)
Avoid overwatering or letting the soil dry out completely
Water at the base to prevent fungal diseases
🧪 Fertilizing
Use a high-nitrogen fertilizer every 2–3 weeks in early growth
Switch to phosphorus-rich fertilizer once bulbs start forming
Stop fertilizing when tops start falling over before harvest
🐛 Common Onion Pests and Diseases
While onions are relatively pest-resistant, they still have a few enemies:
🔍 Pests
Onion Maggots: Larvae tunnel into bulbs—use row covers to protect seedlings
Thrips: Tiny bugs causing silvery streaks on leaves—spray with neem oil
Cutworms: Attack seedlings—protect with collars around base
🚫 Diseases
Downy Mildew: Yellow spots on leaves in humid conditions
Purple Blotch: Dark lesions on foliage—improve air flow and avoid overhead watering
Neck Rot: Post-harvest issue caused by poor curing or storage
✅ Preventive Tips:
Rotate crops annually
Avoid planting onions where garlic or other alliums grew the previous year
Use disease-resistant varieties when possible
✂️ Harvesting Onions
🔔 Signs Onions Are Ready to Harvest:
Tops begin to yellow, wilt, and fall over
Bulbs reach expected size
Outer skin starts forming papery layer
⛏️ How to Harvest:
Gently loosen soil with a fork and lift onions by hand
Let them dry on the surface for a day or two (weather permitting)
🧺 How to Cure and Store Onions
Proper curing and storage can keep your onions fresh for up to 6 months!
🔥 Curing Process:
Place onions in a shaded, well-ventilated area for 10–14 days
Allow outer layers to dry and necks to tighten
Trim tops to 1 inch and roots to ½ inch
❄️ Storage Tips:
Store in mesh bags, crates, or braided bundles
Keep in cool, dry, dark space (32–40°F)
Avoid refrigerators—moisture promotes rot
Check regularly for soft or sprouting bulbs
✅ Avoid storing near potatoes—they release moisture and gases that cause spoilage.
Growing Green Onions and Scallions
No space? No problem. Green onions (scallions) are perfect for windowsills and small pots.
Quick Guide:
Use onion sets or leftover root ends from kitchen
Plant in shallow trays or jars with water
Harvest in 2–3 weeks and regrow multiple times!
💡 Pro tip: Place onion scraps in a glass of water and watch them regrow on your kitchen counter—zero waste, endless supply!
