How To Harvest Walla Walla Onions

Knowing how to harvest Walla Walla onions at the right time is the key to enjoying their famously sweet, mild flavor. This simple step-by-step guide will walk you through the entire process, from spotting the perfect moment to pull them to curing them for long-term storage.

Walla Walla onions are a sweet, long-day variety that need a full growing season to develop their signature juicy crunch. Unlike storage onions, they have a higher water content, which makes them incredibly sweet but also means they need a little extra care during harvest. If you pick them too early, they won’t reach their full size. If you wait too long or handle them wrong, they can bruise and spoil quickly. Let’s get your onions out of the ground and ready for your kitchen.

This is the main event. Following these steps carefully will ensure you get the best quality onions from your garden.

Step 1: Recognize the Signs of Maturity

Walla Wallas are typically ready for harvest in mid-to-late summer, about 90-120 days after planting. Don’t just go by the calendar, though. Look for these visual cues in your garden:

Top Growth Falls Over: The green onion tops (the necks) will start to weaken and flop over naturally. This is the plant’s signal that it has finished bulbing.
Yellowing and Browning: The leafy tops will begin to turn yellow and then brown, starting from the tips down.
Papery Skin: The outer skin of the onion bulb, just at the soil surface, will start to feel dry and papery to the touch.

Step 2: Stop Watering

About one to two weeks before you plan to harvest, stop watering your onion bed. This crucial step allows the outer layers of the onion to begin drying and curing while still in the ground. It helps prevent rot and prepares them for storage.

Step 3: Choose the Right Day

Pick a day for harvest that is dry and sunny. Avoid harvesting after rain or when the soil is muddy. Wet soil can cling to the bulbs, and excess moisture at this stage invites fungal diseases. A breezy day is ideal for starting the curing process right away.

Step 4: Loosen the Soil and Lift Gently

This is where gentleness is key. Do not simply yank the onions by their tops.

Use a garden fork or a small hand trowel to carefully loosen the soil around each bulb. Insert the tool about 6 inches away from the stem to avoid stabbing the onion.
Gently lift the soil underneath the bulb to break the roots’ hold.
Then, carefully pull the onion up by its base, cradling the bulb with your hand. The tops are still attached but may be brittle, so handle with care to avoid breaking them off prematurely.

Step 5: Initial Field Curing

If the weather is warm and dry, you can leave the harvested onions right on the garden soil for a day or two. Lay them out in a single layer with the tops covering the bulbs. This sun bath helps kill any root fungi and starts the drying process. If rain is forcasted, you must move them to a covered location immediately.

What to Do with Damaged Onions

As you harvest, immediately sort your onions. Any bulbs that are bruised, cut by your tool, or show signs of soft spots should be set aside. These will not cure or store well. Use these onions first in your cooking within a week or two.

Step 6: The Essential Curing Process

Curing is not optional for storage; it’s essential. It dries the outer layers and the neck (where the tops meet the bulb) to seal the onion and prevent moisture loss and rot.

Location: Find a warm, dry, well-ventilated spot out of direct sunlight. A covered porch, garage, shed, or a well-ventilated barn is perfect.
Method: Spread the onions out in a single layer on a flat surface. You can use old window screens propped up on sawhorses for excellent air circulation, or a simple wooden rack. A fan in the room can help improve airflow.
Duration: Let them cure for about two to three weeks. The tops and outer skin should become completely papery and rustle when touched. The neck should be totally dry and tight.

Step 7: Final Trimming and Storage

Once curing is complete, it’s time to prep your onions for their storage bin.

Trim the Roots: Use clean scissors or pruners to snip off the dried roots at the base of the bulb.
Trim the Tops: Cut the dried tops down to about 1 to 2 inches above the bulb. Don’t cut too close to the bulb itself.
Final Sort: Gently brush off any remaining dry soil. Give each onion a light squeeze; it should feel very firm. Any soft onions should be used right away.

Step 8: Choosing the Best Storage Method

Remember, Walla Wallas are sweet onions with high water content. They won’t last as long as a pungent storage onion, but with proper care, you can enjoy them for months.

Ideal Conditions: Store in a cool (35-45°F / 2-7°C), dark, and dry place with good air circulation. A basement, root cellar, or unheated garage (that doesn’t freeze) is ideal.
Containers: Use mesh bags, old nylon stockings (tying a knot between each onion), or well-ventilated crates/baskets. Never store them in sealed plastic bags, as this traps moisture and causes rot.
Check Regularly: Every few weeks, check your stored onions. Remove any that have become soft or show signs of sprouting to prevent them from spoiling the others.

Common Harvesting Mistakes to Avoid

Harvesting Too Early: Patience is a virtue. Let the tops fall over naturally for full bulb development.
Pulling, Not Lifting: Yanking can damage the bulb and seperate the top from the root, ruining the onion.
Skipping the Cure: Putting uncured onions into storage is the fastest way to lose your entire harvest to mold.
Storing with Moist Tops: If the necks aren’t fully dry, rot will start there and work its way down.

FAQ: Your Walla Walla Onion Questions Answered

How do I know when my Walla Walla onions are ready to pick?

Look for the tops falling over and turning brown, and the outer bulb skin becoming papery. This usually happens in late July or August, depending on your planting date.

Can you eat Walla Walla onions right after harvest?

Absolutely! Fresh, uncured Walla Wallas are incredibly juicy and sweet. Just brush off the dirt and use them. The curing process is specifically for extending their storage life.

How long can you keep Walla Walla onions after picking?

Properly cured and stored in ideal conditions, they can last 2 to 4 months. Their high sugar and water content means they have a shorter shelf life than other onions, so enjoy them sooner rather than later.

Why are my harvested onions not getting dry during curing?

The air is likely too humid or there isn’t enough ventilation. Try adding a fan to the room to move air around, and make sure they are not piled on top of each other. Spreading them out more can really help.

What’s the best way to harvest onions without damaging them?

Always loosen the soil with a tool first. Gently lift from beneath the bulb instead of pulling hard on the fragile tops. This prevents bruising and breaks.

My onion tops haven’t fallen over, but it’s getting late in the season. What should I do?

You can encourage maturity by gently bending the tops over yourself and then stopping water. Sometimes, especially in cooler summers, they need a nudge. Wait about a week after bending before you start lifting them.