Virginia’s onion season begins in early spring, with sets going in as soon as the soil is dry enough to work. Knowing exactly when to plant onions in Virginia can make the difference between a bumper crop and a disappointing harvest. The state’s varied climate, from the mountains to the coast, means timing shifts slightly depending on where you live.
Onions are cool-season crops that need specific day lengths to form bulbs. In Virginia, you are mostly growing long-day or intermediate-day varieties. The key is getting them in the ground early enough so they mature before summer heat sets in, but late enough to avoid a hard freeze that kills young plants.
When To Plant Onions In Virginia
The short answer is: plant onion sets or transplants in late February through early April, depending on your region. For seeds, start them indoors 8-10 weeks before your last frost date. In coastal areas like Virginia Beach, you can plant as early as late February. In the mountainous west, wait until mid-April.
Soil temperature matters more than calendar dates. Onions grow best when soil is at least 40°F (4°C) at planting depth. If the ground is still frozen or waterlogged, wait. Onions can handle light frosts, but prolonged cold below 20°F will damage them.
Understanding Virginia’s Growing Zones
Virginia spans USDA hardiness zones 5b through 8a. This affects your planting window significantly. Here is a quick breakdown:
- Zone 5b-6a (Western mountains, parts of Shenandoah Valley): Last frost around April 20-May 10. Plant sets in early to mid-April.
- Zone 6b-7a (Central Virginia, Richmond area): Last frost around April 10-20. Plant sets in late March to early April.
- Zone 7b-8a (Tidewater, Hampton Roads, Eastern Shore): Last frost around March 20-April 5. Plant sets in late February to mid-March.
Check your specific zip code’s frost dates online. Your local extension office is a reliable resource for exact timing.
Planting Methods And Their Timing
You have three main ways to start onions: seeds, sets, or transplants. Each has a different timeline.
Starting From Seeds
Onion seeds need a long growing season. Start them indoors 8-10 weeks before your last expected frost. For most of Virginia, that means starting seeds in January or early February. Keep them under grow lights or in a sunny window. Harden them off gradually before transplanting outside.
Seed-grown onions take longer to mature but offer more variety. You can grow unusual types like ‘Walla Walla’ or ‘Red Burgundy’ that are hard to find as sets.
Using Onion Sets
Sets are small, dormant bulbs sold in bags. They are the easiest method for beginners. Plant them directly in the garden as soon as the soil is workable. In Virginia, this is typically late February through April. Sets mature faster than seeds, often in 90-100 days.
Choose sets that are about the size of a marble. Larger sets sometimes bolt (go to flower) instead of forming good bulbs. Plant them 1 inch deep, with the pointy end up, spaced 4-6 inches apart.
Transplants From Nurseries
Many garden centers sell onion transplants in spring. These are young plants started from seed by professionals. They are ready to go in the ground after your last frost. In Virginia, that is usually March through May, depending on your zone.
Transplants give you a head start without the hassle of indoor seed starting. Plant them at the same depth they were growing in the pot. Water well after planting.
Step-By-Step Planting Guide
Follow these steps for best results with your Virginia onion crop:
- Prepare the soil: Onions need loose, well-drained soil with plenty of organic matter. Work in compost or aged manure a few weeks before planting. Remove rocks and break up clods.
- Check soil temperature: Use a soil thermometer. Wait until it reads at least 40°F at 2 inches deep. If it is colder, hold off.
- Plant at the right depth: For sets, push them into the soil so the tip is just at or slightly below the surface. For transplants, plant them at the same depth as in their container.
- Space properly: Space sets 4-6 inches apart in rows 12-18 inches apart. For larger bulbs, give them more room. Closer spacing yields smaller onions.
- Water in: Give them a good soak after planting. Keep the soil consistently moist but not waterlogged. Onions have shallow roots and dry out quickly.
- Mulch: Apply a thin layer of straw or grass clippings to retain moisture and suppress weeds. Onions hate competition from weeds.
Regional Timing Variations In Virginia
Virginia’s geography creates distinct microclimates. Here is more detail for each region:
Coastal Virginia And Tidewater
Areas like Norfolk, Virginia Beach, and the Eastern Shore have mild winters and early springs. Plant onion sets in late February to mid-March. The soil warms quickly here. You can often harvest by late June or early July. Be careful of heavy spring rains that can rot bulbs in heavy clay soil.
Central Virginia And Piedmont
Richmond, Charlottesville, and Lynchburg fall in zones 6b-7a. Plant sets in late March to early April. The last frost usually occurs around April 10-20. If you plant too early, a late freeze can damage young growth. Keep row covers handy for protection.
Western Virginia And Mountains
Roanoke, Blacksburg, and the Shenandoah Valley have colder, longer winters. Plant sets in mid-April to early May. The growing season is shorter, so choose faster-maturing varieties. Consider using transplants instead of seeds to save time.
Choosing The Right Onion Variety For Virginia
Onions are classified by day length. Virginia sits in a transition zone where both intermediate-day and long-day varieties work. Here are recommendations:
- Intermediate-day onions: These form bulbs when day length reaches 12-14 hours. They are ideal for most of Virginia. Varieties include ‘Candy’, ‘Super Star’, and ‘Red Candy Apple’.
- Long-day onions: These need 14-16 hours of daylight. They work well in northern Virginia and higher elevations. Try ‘Yellow Sweet Spanish’, ‘Walla Walla’, or ‘Redwing’.
- Short-day onions: These need 10-12 hours of daylight. They are not recommended for Virginia except possibly in the far south. They will bulb too early and produce small onions.
Ask at your local garden center what varieties perform best in your area. They know what works locally.
Common Mistakes When Planting Onions In Virginia
Avoid these pitfalls to ensure a successful harvest:
- Planting too early: If the soil is too cold or wet, sets can rot before they root. Wait for proper conditions.
- Planting too late: Onions need cool weather for leaf growth. If you plant in May, they may not have time to bulb before summer heat.
- Overwatering: Onions need consistent moisture, but soggy soil leads to rot. Improve drainage with raised beds if needed.
- Ignoring day length: Growing short-day onions in Virginia will give you tiny bulbs. Stick with intermediate or long-day types.
- Not hardening off transplants: If you start seeds indoors, gradually expose them to outdoor conditions over a week. Otherwise, they may shock and die.
Caring For Onions After Planting
Once your onions are in the ground, proper care is essential. Here is what to do:
Watering: Onions need about 1 inch of water per week. During dry spells, water deeply. Stop watering once the tops start to fall over, which signals maturity.
Fertilizing: Onions are heavy feeders. Apply a balanced fertilizer (10-10-10) at planting time. Side-dress with nitrogen every 2-3 weeks until bulbs start forming. Too much nitrogen late in the season can delay bulbing.
Weeding: Keep the onion bed weed-free. Weeds compete for nutrients and water. Hand-pull carefully to avoid disturbing shallow roots.
Pest and disease management: Watch for onion thrips, which cause silvery streaks on leaves. Use insecticidal soap if needed. Fungal diseases like downy mildew thrive in wet conditions. Space plants for good air circulation.
Harvesting And Storing Onions
Onions are ready to harvest when the tops turn yellow and fall over. This usually happens in late June through August, depending on planting time. Do not wait too long or bulbs may split.
To harvest, gently loosen the soil with a fork and pull the onions. Let them cure in a warm, dry, well-ventilated place for 2-3 weeks. Cut off the tops and roots before storing. Store in a cool, dark place with good airflow.
Properly cured onions can last several months. Check them regularly and remove any that show signs of rot.
Frequently Asked Questions
Can I plant onions in the fall in Virginia?
Yes, you can plant overwintering onion sets in fall for an early spring harvest. Plant them in September or October in zones 7b-8a. They will grow slowly over winter and mature in late spring. This works best in coastal areas with milder winters.
What is the best onion variety for beginners in Virginia?
‘Candy’ is a reliable intermediate-day onion that performs well across the state. It is sweet, stores reasonably well, and is forgiving of imperfect conditions. ‘Yellow Granex’ (the Vidalia type) also works in central and southern Virginia.
How deep should I plant onion sets?
Plant sets about 1 inch deep, with the pointed tip just at or slightly below the soil surface. If you plant too deep, the bulb may not form properly. Too shallow, and the roots may dry out.
Do onions need full sun in Virginia?
Yes, onions need at least 6-8 hours of direct sunlight daily. Less sun results in smaller bulbs and weaker plants. Choose a spot in your garden that gets full sun all day.
Can I grow onions in containers in Virginia?
Absolutely. Use a container at least 12 inches deep with drainage holes. Fill with loose potting soil. Plant sets 3-4 inches apart. Water frequently, as containers dry out faster than garden beds. Place in a sunny spot.
Final Tips For Success
Onions are one of the most rewarding crops for Virginia gardeners. They are low-maintenance once established and store well for winter use. The most critical factor is timing. Get them in the ground at the right moment, and you are most of the way there.
Keep a garden journal noting your planting dates and results each year. Over time, you will learn the perfect window for your specific microclimate. Talk to neighbors who garden—they often have valuable local knowledge.
Remember that onions are heavy feeders. Prepare your soil well in advance. Add compost or well-rotted manure a month before planting. This gives nutrients time to integrate into the soil.
Do not be afraid to experiment with different varieties. What works in one part of Virginia may not work in another. Try a few types each year until you find your favorites.
With careful timing and basic care, you will enjoy a bountiful onion harvest that lasts through the winter. Happy planting in Virginia.