The Walla Walla onion, classified as Allium cepa, is a delicious variety of sweet onions in the Amaryllidaceae family.
This variety of sweet onions is a long-day variety that is named for the region in Washington State in which they are grown and harvested.
Keep reading to learn about Walla Walla onions, including their history, health benefits, and ways to enjoy them!
Looking for Walla Walla Onion seeds? Check availability.
History of Walla Walla Sweet Onions
Walla Walla onions are named for the specific county in Washington State where they were first cultivated by French soldier Pete Pieri.
In 2007, these onions were officially declared Washington’s state vegetable.
Pieri came to the Walla Walla Valley in the early 1900s, bringing the original sweet onion seed with him from Italy. He developed this variety by trait selection, growing specific traits until he achieved the perfect size, sweetness, and shape of Walla Walla onions.
“Walla Walla” is actually a Native American term meaning “many waters,” and they are cultivated in their namesake’s small town. Walla Walla, a small town in Washington State, has often been called an “oasis in the desert,” because of the abundance of greenery in an otherwise arid region.
Today you can find Walla Walla sweet onions in specialty grocery stores, at farmer’s markets, and in online nurseries across the United States.
Walla Walla onions grow to medium and large sizes and they are globular shaped with rounded ends.
The bulb of the onion is encased in papery skin that is dry, flaky, and yellowish-brown in color. Underneath the parchment-like skin is the white flesh of the onion, which is nearly translucent in color.
Underneath the brittle exterior of Walla Walla onions is pristine white flesh that is firm, with a signature crunch. This sweet onion is juicy, with many thin layers of ‘rings.’
These onions are prized for their consistently mild and sweet flavor profile when raw. When cooked, they develop a sweet and warm flavor, due to their high sugar and water content.
This sweet flavor is a result of the low-sulfur content in the soil in which these onions are planted.
Ways to Enjoy Walla Walla Onions
Walla Walla onions are best enjoyed raw or cooked! Considered a true raw-eating onion because of its mild flavor, this variety is delicious and fresh when mixed into green or potato salads or layered onto a sandwich.
The onion can also be cooked into soups, stews, casseroles, or even fried into onion rings. It pairs well with poultry, fish, and other veggies such as cucumber, tomatoes, and asparagus.
The hollow stems of Walla Walla onion plants can be harvested for green onions once they reach 8 inches tall.
You can add these onions to nearly any dish for a flavorful addition.
Walla Walla onions contain vitamin C, which promotes a healthy immune system and improves your overall health.
They also contain potassium, iron, and calcium, vital to bodily function. These onions help reduce bad cholesterol and promote a healthy heart.
These onions are an excellent source of fiber, which promotes healthy digestion and lowers your chances of having a gastric ulcer. It also helps maintain the healthy bacteria that are present in your gut and intestinal tract.
Onions contain a powerful antioxidant called quercetin, which lowers the chances of contracting some cancers, helps prevent heart disease, reduces inflammatory swelling, and helps maintain blood sugar.
Growing Your Own
Walla Walla sweet onions are considered long-day onions, which means they need around 14-15 hours of daylight each day. You will need to consider this when you prepare the site for planting.
These onions must meet specific quality regulations and be grown in the designated region to be labeled as a “Walla Walla” variety.
How to Grow Walla Walla Onions
Walla Walla onions are easy to grow and should be planted in early spring once the ground is workable. You can plant your seeds directly into the ground or use raised beds.
The soil quality is absolutely vital when growing your own onions because they grow as bulbs beneath the soil surface.
If you choose to go with raised beds, you’ll need well-draining, organic soil, that can be amended with organic compost as needed to help your plants thrive.
If you’re planting your seeds directly into native soil, you can amend it to improve the nutrient balance on an as-needed basis with an organic soil mix. You can also add organic compost or other rich organic matter if it’s needed to help balance the nutrients in your soil.
These onions need well-draining soil with a pH of 6.0-6.8, so be sure to test your soil before adding any extra nutrients.
Space onions at least 6 inches apart in rows that are at least 12 inches apart. Plant seeds around ¼ inch deep into the soil and lightly cover with soil.
Onions aren’t the best at soaking up water, with shallow roots, so it’s vital to keep the soil moist. If the top inch of soil is dry, your plants need to be watered.
Slow, deep watering promotes healthy roots, so a good rule of thumb for watering Walla Walla onions is to make sure they have one inch of water each week.
Keep your plants well-fed with a continuous-release plant food like Miracle-Gro Organic Plant Nutrition Granules.
As bulbs form, onions naturally push toward the soil surface. The tops of the bulbs will expose themselves to the sun, drying the top skin out until it feels papery.
Once you can see the tops of most bulbs on the ground, you can gently lift the onions to break them free from their roots.
It’s important to leave them on the ground where they were growing for at least a week after breaking them loose from the roots. Once the tops of all the bulbs are thoroughly dry, cut them off and remove the bulbs from the soil.
Remember that a hard freeze can damage young seedlings, but onions are generally cold-hardy as long as the ground doesn’t freeze.
The most common diseases you may face with this onion variety are fungal spots and blight. They can also suffer from rotting roots, stems, and crowns. The best way to prevent these issues is to make sure you give each plant adequate space to grow.
Water your plants in the mornings so they have time to dry by sunset, but avoid watering them overhead. Fungicides containing neem oil can be used to combat these issues if preventative measures don’t cut it.
Common pests to watch your plants for include aphids and thrips, which can be combatted by pesticides that also contain neem oil.
Where to Buy
When purchasing onion seeds, always make sure to use a reliable source. We recommend buying Walla Walla onion seeds from the popular online retailer, Hoss Tools!
Try Walla Walla Sweet Onions!
If you’re looking for a sweet onion that can be used in nearly any recipe, look no further than Walla Walla onions! They are fairly easy to grow and produce mildly sweet flavorful vegetables.
Check out our guide on Onions to learn more about different varieties of onions, how to plant them, and recipes to incorporate them.