What To Know
- If you’re looking to cultivate these culinary gems in your own backyard, learning how to grow Walla Walla onions from seed is a rewarding journey.
- Walla Walla onions are a variety of sweet onion that originated in the Walla Walla Valley of Washington state.
- Place the tray in a warm, sunny location or under grow lights.
Walla Walla onions are renowned for their sweet, mild flavor and colossal size. Their distinctive, almost pear-shaped bulb and thin, papery skin make them a favorite among chefs and home gardeners alike. If you’re looking to cultivate these culinary gems in your own backyard, learning how to grow Walla Walla onions from seed is a rewarding journey.
Understanding Walla Walla Onions
Walla Walla onions are a variety of sweet onion that originated in the Walla Walla Valley of Washington state. They are known for their:
- Sweet, Mild Flavor: Unlike pungent yellow onions, Walla Wallas have a delicate sweetness that makes them perfect for salads, grilling, and caramelizing.
- Large Size: These onions can grow to impressive sizes, often reaching 6-8 inches in diameter.
- Distinctive Shape: Their pear-shaped bulbs with a slightly flattened top are easily recognizable.
- Thin, Papery Skin: The skin is typically a light brown color and peels off easily.
Choosing the Right Seeds
The first step in growing Walla Walla onions from seed is selecting high-quality seeds. Look for seeds from reputable sources, as seed quality can significantly impact your harvest.
Consider these factors when choosing seeds:
- Variety: While Walla Walla is the most popular sweet onion variety, there are other similar options like Candy and Sweet Spanish onions. Choose the variety that best suits your taste preferences.
- Freshness: Check the seed packet for an expiration date. Fresh seeds will have a higher germination rate.
- Origin: Seeds from local sources or those specifically bred for your climate will usually perform better.
Sowing the Seeds: Starting Indoors
Walla Walla onions are best started indoors, especially in colder climates. This gives them a head start and allows you to control their growth environment.
Timing: Start seeds indoors 6-8 weeks before the last frost date in your area.
Materials:
- Seed Starting Trays: These trays provide individual cells for each seed, making it easy to transplant later.
- Seed Starting Mix: Use a sterile, seed-starting mix that drains well.
- Watering Can: Water the seeds gently, avoiding overwatering.
- Grow Lights: Provide artificial light, especially if you don’t have a sunny windowsill.
Steps:
1. Fill the seed starting tray: Fill the cells with seed starting mix, leaving about half an inch of space at the top.
2. Sow the seeds: Plant one seed per cell, about ¼ inch deep.
3. Water gently: Mist the seeds lightly with water.
4. Cover the tray: Cover the tray with a clear plastic dome or wrap to retain moisture.
5. Provide light: Place the tray in a warm, sunny location or under grow lights.
6. Maintain moisture: Keep the soil moist but not soggy.
7. Thin seedlings: Once the seedlings have two true leaves, thin them to the strongest one per cell.
Hardening Off and Transplanting
Before transplanting your onion seedlings outdoors, it’s essential to harden them off. This process gradually acclimates them to the outdoor environment, making them more resilient.
Hardening Off:
1. Start gradually: Over a week, expose the seedlings to increasing amounts of sunlight and wind.
2. Begin with a few hours: Start with a few hours of outdoor exposure each day, gradually increasing the time.
3. Protect from extreme conditions: Shield the seedlings from strong winds, direct sun, and cold temperatures.
Transplanting:
1. Prepare the soil: Choose a sunny location with well-drained soil. Amend the soil with compost or aged manure for optimal growth.
2. Space the seedlings: Space the seedlings 12-18 inches apart, depending on the variety.
3. Dig holes: Dig holes large enough to accommodate the roots without disturbing them.
4. Transplant carefully: Gently remove the seedlings from their trays and place them in the holes.
5. Water thoroughly: Water the seedlings deeply after transplanting.
Caring for Your Walla Walla Onions
Once your Walla Walla onions are planted, providing them with the right care is crucial for a bountiful harvest.
Watering: Water consistently, especially during dry periods. Aim to keep the soil moist but not waterlogged.
Fertilizing: Fertilize your onions with a balanced fertilizer every 4-6 weeks. Avoid using fertilizers high in nitrogen, as it can promote leafy growth at the expense of bulb development.
Weeding: Keep the area around your onions free of weeds, which can compete for nutrients and water.
Mulching: Apply a layer of mulch around the base of the onions to help retain moisture and suppress weeds.
Harvesting and Storing
Walla Walla onions are ready for harvest when the tops begin to fall over and the bulbs feel firm.
Harvesting:
1. Use a garden fork: Gently loosen the soil around the onion bulb with a garden fork.
2. Lift the onion: Carefully lift the onion from the ground, avoiding damage to the bulb.
3. Cut the tops: Cut the tops off about an inch above the bulb.
Storing:
- Cure the onions: Allow the onions to dry in a cool, well-ventilated area for a few days.
- Store in a cool, dry place: Store the cured onions in a cool, dry location, such as a basement or pantry.
- Avoid freezing: Walla Walla onions do not freeze well.
Troubleshooting Common Problems
While Walla Walla onions are relatively easy to grow, they can be susceptible to certain pests and diseases. Here are some common problems and how to address them:
- Onion fly: Onion flies lay eggs in the soil, and the larvae feed on the roots. To prevent onion flies, cover the soil with row covers or use diatomaceous earth.
- Onion thrips: These tiny insects suck sap from the leaves, causing damage. Use insecticidal soap or neem oil to control thrips.
- Downy mildew: This fungal disease causes yellowing and spotting on the leaves. To prevent downy mildew, choose disease-resistant varieties and avoid overhead watering.
- Neck rot: This fungal disease can occur during storage. To prevent neck rot, cure the onions properly and store them in a cool, dry place.
A Sweet Reward: Enjoying Your Walla Walla Onions
Growing Walla Walla onions from seed is a satisfying experience that rewards you with delicious, homegrown produce. Whether you enjoy them raw in salads, grilled on the barbecue, or caramelized in a savory dish, their sweet, mild flavor will enhance any meal.
What You Need to Know
Q: Can I grow Walla Walla onions in containers?
A: Yes, you can grow Walla Walla onions in containers. Choose a container at least 12 inches wide and deep and use a well-draining potting mix.
Q: How long does it take for Walla Walla onions to mature?
A: Walla Walla onions typically mature in 100-120 days from planting.
Q: Can I save seeds from my Walla Walla onions?
A: While you can save seeds from your onions, it’s not recommended for Walla Walla onions. Hybrid varieties like Walla Walla do not produce true-to-type seeds.
Q: What are some other sweet onion varieties I can grow?
A: Other sweet onion varieties you can try include Candy, Sweet Spanish, and Vidalia onions.
