Type	Daylight	Region	Examples
Long-Day	14–16 hrs	North	Walla Walla, Copra
Short-Day	10–12 hrs	South	Red Creole, Grano
Intermediate	12–14 hrs	Central Zones	Candy, Super Star

Picking the Right Onion Type for Your Area

• Long-day onions: If you live up north—think above the 37th parallel—long-day onions are your best bet. These varieties need about 14 to 16 hours of daylight to start bulbing, so they do well in places with long summer days. Some popular ones include ‘Walla Walla’, ‘Yellow Sweet Spanish’, and ‘Copra’.
• Short-day onions: If you’re in the South, short-day onions are your go-to. They only need 10 to 12 hours of daylight to start forming bulbs. Try ‘Red Creole’, ‘Texas Early Grano’, or ‘White Bermuda’.
• Intermediate-day onions: If you’re somewhere in the middle of the country, these give you some flexibility. Varieties like ‘Candy’ and ‘Super Star’ are solid choices.

Timing Is Everything: When to Start Seeds

• Colder regions: Start your seeds indoors about 10 to 12 weeks before your last expected frost. That usually means late January or early February.
• Warmer climates: You can start seeds outdoors in mild winters or indoors around December or January.
• Germination time: You should see the seeds sprout in about 7 to 10 days if your soil stays between 65°F and 70°F.
• Transplant readiness: Wait until seedlings are at least 6 inches tall and have a strong base before moving them outside.

Setting Up Your Seed-Starting Station

• What you’ll need:
  • Seed trays or shallow containers with good drainage
  • Seed-starting mix that holds moisture but drains well
  • Grow lights or a sunny window with 12–14 hours of daylight
  • Plant labels to keep track of varieties
• Planting depth and spacing: Fill trays with moist seed-starting mix, plant seeds about ¼ inch deep and ½ inch apart, then cover lightly. Set trays in a warm spot and keep them moist.
• Light and rotation: Once the seeds sprout, move the trays somewhere bright, and rotate them every few days if they’re not under grow lights. This keeps the seedlings from leaning.

Caring for Your Seedlings Indoors

• Thinning: When seedlings hit about 2 inches tall, thin them so each plant has roughly an inch of room.
• Temperature: Keep the room around 60–65°F to avoid fast, leggy growth.
• Water and nutrients: Water when the top of the soil feels dry. Feed with diluted organic fertilizer like fish emulsion every 10 to 14 days.
• Trimming: Every couple of weeks, trim the tops of the seedlings down to about 3 inches. This encourages better root growth.

Hardening Off and Getting Ready to Transplant

Hardening off steps:

1. Place seedlings outside in a shady spot for about 1–2 hours.
2. Gradually increase the time and light exposure each day.
3. Do this for 7–10 days before transplanting.

Transplant tips:

• Choose a sunny area with well-drained, loose soil.
• Carefully separate the seedlings.
• Plant each seedling so the white base is buried, but not the green top.
• Keep plants about 4–6 inches apart and leave 12–18 inches between rows.

Giving Your Onions What They Need Outdoors

• Soil: Onions love full sun and slightly acidic to neutral soil (pH 6.0–7.0). Simply loosen the ground about eight inches deep and work in some compost or aged manure.
• Mulch and weeds: Add mulch like straw or leaves around the onions to hold moisture and block weeds. Pull weeds regularly—onions don’t like the competition.
• Watering: Onions need consistent moisture, about 1 inch of water per week. Keep the soil damp, not soaked, to avoid rot.

Feeding Your Plants for Bigger Bulbs

• Early growth: Use a balanced fertilizer (10-10-10) every few weeks early in the season.
• Bulb formation: Once bulbs start forming, grab a 5‑10‑10 fertilizer to boost phosphorus and potassium.
• Stop feeding: Once bulbs are halfway to full size, stop fertilizing to allow natural curing.

Keeping Pests and Diseases at Bay

Common pests:

• Cover your rows and rotate crops to keep onion maggots away.
• Thrips suck on leaves and leave silvery streaks. Neem oil or insecticidal soap works well.

Common diseases:

• Downy mildew and pink root can be managed with crop rotation and good airflow.
• Fusarium rot shows up in wet, poorly drained soil—avoid overwatering.

Knowing When and How to Harvest

• Signs of maturity: Onion tops will turn yellow and fall over naturally when they’re ready to harvest.

Harvest steps:

1. Just grab a fork and gently wiggle it in the soil to free up the bulb.
2. Let onions sit on top of the soil for a day or two if it’s dry.
3. Move them to a shady spot to cure for a few weeks.

Curing and Storing Your Onions

• Curing: Lay the onions in a warm, dry spot with good airflow. Let them dry for 2–3 weeks until the necks and skins are fully dried.
• Trimming and storing: Cut tops down to about 1 inch and trim roots. Store onions in a cool, dry place using mesh bags, baskets, or braided strings. Don’t use plastic—it traps moisture.

Solving Common Onion Problems

• Yellowing leaves: Could mean a lack of nitrogen or inconsistent watering. Feed with a nitrogen-rich fertilizer and water more consistently.
• Bolting: Happens from stress like temperature swings or transplant shock. Use bolt-resistant varieties and handle seedlings gently.
• Small bulbs: Usually caused by planting too late, not spacing properly, or feeding too much nitrogen late in the season. Start seeds early, give them room, and stop feeding once bulbs start forming.

Conclusion

Growing onions from seeds may take more effort, but it pays off with strong, flavorful bulbs that store better and last longer. With the right timing, prep, and care, anyone can grow a garden full of onions from seed—even if you’re just getting started. Take it step by step, and you’ll be harvesting like a pro in no time.

Key takeaway: Starting onions from seeds gives you better variety, healthier plants, and longer-lasting bulbs—making it totally worth the extra effort.

FAQs

Can I grow onions year-round in warmer climates?

In warmer regions, you can grow short-day onions during the cooler months. Just avoid trying to grow them in peak summer heat when they tend to bolt.

Do onion plants need to be staked or supported?

Nope! Onions grow low to the ground and don’t require staking. As long as they’re spaced properly and get enough light, they’ll stand up just fine on their own.

How do I grow onions in containers?

Use a large pot that’s at least 10–12 inches deep with well-draining soil. Space each onion 4–6 inches apart, and make sure the container gets full sun.

Why are my onions not forming bulbs?

This usually happens if you chose the wrong type of onion for your region, planted too late, or if the plants didn’t get enough sunlight or nutrients during the early stages.

Is it okay to grow onions next to other vegetables?

Yes! Onions make great companions for carrots, lettuce, beets, and even tomatoes. Just avoid planting them too close to legumes like peas or beans.