Walla Walla onions mature in late July, so harvest when tops flop over and necks begin to soften. If you are wondering how to harvest walla walla onions, the process is simpler than you might think, but timing and technique matter a great deal for long-term storage.
These sweet onions are a favorite among gardeners because of their mild, sugary flavor. Unlike storage onions, they have a higher water content, which makes them more delicate. You need to handle them with care from the moment you pull them from the soil.
In this guide, we will walk through every step. You will learn when to dig, how to cure, and how to store them so they last for months. Let’s get started.
Why Harvest Timing Matters
Picking Walla Walla onions too early means they will not have reached their full size. Picking them too late can cause them to rot in the ground or start re-growing. The key is to watch the plant’s signals closely.
Walla Walla onions are day-length sensitive. They form bulbs when daylight hours reach a certain length. In the Pacific Northwest, where they are famous, this usually happens in mid to late July. The exact date depends on your local climate and when you planted the sets.
Signs That Your Onions Are Ready
Do not rely on the calendar alone. Your plants will tell you when they are ready. Here are the main signs to look for:
- The green tops (foliage) will start to yellow and fall over naturally.
- The neck of the onion, where the leaves meet the bulb, becomes soft and pliable.
- The bulb pushes up slightly out of the soil, showing its shoulders.
- The outer skin of the bulb turns papery and dry.
If the tops are still standing tall and green, the onions are still growing. Wait another week and check again. It is better to wait a few extra days than to harvest prematurely.
How To Harvest Walla Walla Onions
Now that you have identified the right time, it is time to get your hands dirty. The process involves loosening the soil, lifting the bulbs, and preparing them for curing. Follow these steps carefully to avoid bruising.
Step 1: Loosen The Soil
Walla Walla onions have shallow root systems. They do not sit deep in the ground, but the soil can be compacted. Use a garden fork or a trowel to gently loosen the soil around each bulb.
Insert the fork about 4 to 6 inches away from the bulb. Push the handle down to lift the soil. This cuts the roots and makes it easier to pull the onion out without tearing the base.
Do not pull the onions by their tops if the soil is hard. You will rip the leaves off, leaving an open wound that invites rot.
Step 2: Lift The Bulbs Gently
Once the soil is loose, grasp the onion at the base of the neck, not the leaves. Give it a gentle twist and pull. The bulb should come out easily with the roots attached.
Shake off the excess dirt, but do not wash the onions. Water on the bulb will speed up decay during the curing process. Just brush off the big clumps with your hands.
Place the onions on the ground in a single layer. Do not pile them on top of each other yet. They need airflow around them.
Step 3: Leave Them In The Field
If the weather is dry and sunny, you can leave the onions right where you pulled them. Let them sit on top of the soil for a day or two. This starts the curing process immediately.
If rain is in the forecast, move them under a covered porch or into a greenhouse. Wet conditions will encourage mold. The goal is to dry the outer skin and the neck thoroughly.
Do not cut the tops off yet. The leaves contain moisture and nutrients that will continue to feed the bulb as it cures.
Curing Your Walla Walla Onions
Curing is the most critical step for long-term storage. It dries the outer layers and seals the neck, preventing bacteria and mold from entering. A proper cure takes 2 to 3 weeks.
If you skip this step, your onions will spoil within a few weeks. They will become soft, mushy, and develop a strong odor. Take the time to do it right.
Best Conditions For Curing
You need a warm, dry, and well-ventilated area. A garage, shed, or covered patio works well. The ideal temperature is between 75°F and 85°F. Humidity should be low.
Spread the onions out in a single layer on a wire rack, a screen, or a wooden pallet. Do not use a solid surface like a concrete floor, as it traps moisture underneath.
Make sure the onions are not touching each other. Air needs to circulate around every bulb. If you have a fan, point it at them to increase airflow.
Turning And Checking
Every few days, turn the onions over. This ensures that the bottom side dries evenly. Check for any soft spots or signs of mold. Remove any onions that look bad immediately, so they do not contaminate the others.
After about two weeks, the necks should feel completely dry and papery. The outer skin will be brittle and rustle when you touch it. The roots will be shriveled and dry.
At this point, the onions are cured and ready for storage.
Trimming And Cleaning
Once curing is complete, you need to trim the onions before storing them. This reduces the surface area for bacteria and makes them easier to handle.
Cutting The Tops
Use a clean pair of scissors or garden shears. Cut the dried tops off, leaving about 1 inch of the neck attached. Do not cut too close to the bulb, as this creates an open wound.
If you plan to braid your onions, leave the tops longer. Braiding is a traditional way to store them, and it looks beautiful in a kitchen. But for simple storage, cut them short.
Trimming The Roots
Trim the roots down to about 1/4 inch. Be careful not to cut into the base of the bulb. The root plate is where the onion can re-sprout, but you want it intact for storage.
Brush off any remaining loose skin. Do not peel the onion. The papery layers are protective. Leave them on.
Storing Your Harvest
Walla Walla onions are not the best keepers compared to yellow storage onions. They have a shorter shelf life, usually 1 to 3 months. But with the right conditions, you can enjoy them well into the fall.
Ideal Storage Conditions
Store your cured onions in a cool, dry, dark place. The ideal temperature is between 32°F and 40°F. A basement, root cellar, or a cool pantry works well.
Do not store them in the refrigerator. The humidity is too high, and they will become soft and moldy. Also, avoid plastic bags. They trap moisture and cause rot.
Use mesh bags, wire baskets, or even old pantyhose. The key is to allow air circulation. Hang them or place them on a rack.
Checking For Spoilage
Check your stored onions every week. Remove any that show signs of sprouting, softening, or mold. One bad onion can spoil the whole batch.
If you notice a strong, pungent smell, that is a sign that an onion is breaking down. Find it and remove it quickly.
Keep the onions separate from potatoes. Potatoes release moisture and gases that cause onions to spoil faster.
Common Mistakes To Avoid
Even experienced gardeners make mistakes with sweet onions. Here are the most common pitfalls and how to avoid them.
Harvesting Too Early
It is tempting to pull an onion as soon as it looks big. But if the tops are still green and upright, the bulb is still growing. Harvesting early reduces your yield and the onion will not store well.
Be patient. Wait for the tops to fall over naturally. This is the plant’s way of saying it is done.
Washing The Onions
Do not wash your onions after harvest. Water introduces moisture, which leads to mold and rot. If the onions are muddy, let them dry in the sun and then brush off the dirt.
If you absolutely must clean them, do it right before you use them in the kitchen, not before storage.
Storing In A Humid Area
Walla Walla onions hate humidity. Do not store them in a laundry room, bathroom, or near a sink. The moisture in the air will cause them to sprout or rot.
Always choose the driest spot you can find in your home.
Using Your Fresh Onions
Walla Walla onions are famous for their sweetness. They are excellent eaten raw in salads, sandwiches, and salsas. You can also grill them, caramelize them, or pickle them.
Because they are so mild, they do not bring tears to your eyes like regular onions. This makes them perfect for fresh preparations.
If you have a surplus, consider making onion jam or freezing them. You can chop and freeze them in freezer bags for use in soups and stews. They will lose their crisp texture but retain the flavor.
Frequently Asked Questions
Here are some common questions gardeners have about harvesting and storing Walla Walla onions.
Can I Harvest Walla Walla Onions Earlier If I Want Smaller Bulbs?
Yes, you can harvest them early for immediate use. They will be smaller and less sweet, but still edible. Just remember that they will not store well, so use them within a week.
What Happens If I Leave My Walla Walla Onions In The Ground Too Long?
If you leave them too long, they will start to re-sprout. The bulb will split, and the flavor will become bitter. They may also rot in wet soil. It is better to harvest on time.
Do I Need To Cure Onions If I Plan To Eat Them Right Away?
No, if you are going to eat them within a few days, you can skip curing. Just pull them, brush off the dirt, and use them fresh. Curing is only for long-term storage.
Why Are My Walla Walla Onions Not Getting Big?
This could be due to overcrowding, lack of water, or poor soil fertility. Onions need consistent moisture and nitrogen-rich soil. Make sure they get at least 1 inch of water per week.
Can I Store Walla Walla Onions In The Fridge?
It is not recommended. The fridge is too humid, and the onions will become soft and moldy. Use a cool, dry pantry or cellar instead.
Final Thoughts On Harvesting
Harvesting Walla Walla onions is a rewarding task. With the right timing and a little patience, you will have a bountiful supply of sweet, delicious onions. Remember to cure them properly and store them in a dry place.
Do not rush the process. The extra two weeks of curing will make a huge difference in how long your onions last. And always handle them gently to avoid bruising.
Now you know exactly how to harvest walla walla onions. Get out there and enjoy the fruits of your labor. Your taste buds will thank you.
If you have any more questions, feel free to ask your local extension office or a seasoned gardener. They will have specific tips for your microclimate. Happy harvesting.