Learning how to harvest Walla Walla onions at the right time and in the right way is the key to enjoying their famously sweet, juicy flavor. This guide provides clear, step-by-step instructions to ensure you get the most from your crop, from knowing when they’re ready to proper curing and storage.
These sweet onions are a summer treat, but their high water content makes them more perishable than storage varieties. A successful harvest hinges on timing and technique. Let’s walk through the entire process.
How To Harvest Walla Walla Onions
The actual act of harvesting Walla Walla onions is simple, but it’s the preparation and follow-up that matter most. This section covers the physical harvest, but first, you need to be certain your onions are ready.
Signs Your Walla Walla Onions Are Ready For Harvest
Walla Walla onions are typically ready for harvest in mid to late summer, about 90-110 days after planting sets or transplants. Relying on the calendar is not enough. You must observe the plants themselves for these key indicators.
The most reliable sign is the softening and bending of the onion tops. About a quarter to a third of the tops will fall over naturally as the onion stops growing and begins to enter dormancy. This is the plant’s signal that it’s time.
Next, check the neck of the onion, where the leaves meet the bulb. It should start to feel soft and lose its rigidity. The outer leaves will begin to yellow and dry out. Finally, you can gently brush away a little soil from the shoulder of a bulb to check its size; it should appear plump and have developed its characteristic flattened globe shape.
What Not To Do Before Harvest
A common mistake is to bend over the tops yourself. Let this happen naturally. Forcing the tops over can damage the neck and invite rot. Also, stop watering about a week before you expect to harvest. This allows the outer layers to begin drying and helps prevent mold.
The Step-By-Step Harvesting Process
Once a significant number of tops have fallen over and the weather forecast calls for dry conditions, you are ready to harvest. Follow these numbered steps for the best results.
- Choose a dry, sunny day. Harvesting in wet conditions can introduce moisture that leads to spoilage during curing.
- Using a garden fork or spade, gently loosen the soil about 4-6 inches away from the bulb. Insert the tool and lever it back to lift the soil and bulbs. Avoid stabbing the fork directly into the bulb cluster.
- Carefully grasp the base of the tops and lift the onion from the loosened soil. If the soil is very loose, you may be able to pull them gently by hand, but lifting with a tool first is safer.
- Shake off any excess soil gently. Do not wash the onions or bang them together to remove dirt, as this can cause bruising.
- Lay the harvested onions in a single layer right in the garden row, if conditions are dry and sunny, for an initial airing. Leave them for a few hours to let the sun dry the outer skins.
How To Cure Walla Walla Onions Properly
Curing is the most critical post-harvest step for Walla Walla onions. It dries the outer layers and the neck, sealing the bulb and significantly extending its shelf life. Without proper curing, they will rot quickly.
You need a warm, dry, well-ventilated area out of direct sunlight. A covered porch, garage, shed, or a well-ventilated attic can work perfectly. Direct sun can actually scald the bulbs during curing.
- Lay the onions in a single layer on a flat surface like a screen, rack, or even newspaper. Ensure air can circulate around all sides.
- Alternatively, you can tie them in small bunches by their tops and hang them from a rafter or line.
- Let them cure for two to three weeks. The process is complete when the outer skins are papery and rustle to the touch, the necks are completely dry and tight, and the roots are shriveled.
Preparing Onions For Storage
After curing, you need to prepare the onions for their final storage. This involves a simple trimming and sorting process.
- First, trim the dried tops down to about 1-2 inches above the bulb using clean scissors or pruners. Do not cut too close to the bulb.
- Next, gently rub off any loose dirt and trim the dried roots, being careful not to damage the basal plate at the bottom.
- Sort your onions. Set aside any that have thick, green necks that didn’t cure properly, or any with soft spots, bruises, or cuts. These should be used first, as they will not store well.
Best Practices For Storing Walla Walla Onions
Even when cured, Walla Walla onions are a sweet, high-moisture variety and will not keep as long as pungent storage onions. Under ideal conditions, you can expect 1-3 months of storage.
The goal is to provide a cool, dry, dark, and well-ventilated environment. A basement, root cellar, or unheated garage that stays above freezing is ideal. The optimal temperature range is 35-50°F (2-10°C) with 65-70% humidity.
- Place the cured and trimmed onions in mesh bags, old nylon stockings (tying a knot between each onion), or ventilated crates. Never use plastic bags, as they trap moisture.
- Check your stored onions every few weeks. Remove any that show signs of softening or sprouting immediately to prevent rot from spreading.
- Remember, Walla Walla onions are best enjoyed relatively fresh. Plan to use them within a few months for peak flavor and texture.
Common Harvesting Mistakes To Avoid
Awareness of common errors can save your entire crop. Here are the pitfalls to steer clear of.
Harvesting Too Early Or Too Late
Pulling onions before the tops have fallen over results in small bulbs with thick, green necks that are prone to rot. Waiting too long after tops have fallen, especially in wet weather, can cause the bulbs to rot in the ground or the outer skins to split.
Damaging The Bulbs During Harvest
Yanking onions without loosening the soil can rip the tops right off. Always use a fork to lift them. Also, avoid puncturing or bruising the bulbs with your tools, as this creates an entry point for decay.
Improper Curing Conditions
Curing in a damp, dark, or poorly ventilated space is a recipe for mold. Ensure there is constant air movement. Also, do not skip the curing process entirely, thinking you will just eat the onions right away; even those for immediate use benefit from a short cure to improve skin integrity.
What To Do With Imperfect Or Damaged Onions
Not every onion will be perfect. You will have some with thick necks, small sizes, or minor nicks from your garden fork. These onions are still perfectly edible, but they won’t store.
The solution is to use them first. Chop and freeze them for future cooked dishes, make a large batch of caramelized onions, or use them immediately in your summer recipes. This ensures no part of your harvest goes to waste.
Growing Tips For A Better Harvest
The quality of your harvest begins months earlier in the garden. Following best practices during the growing season sets the stage for an abundant and healthy yield.
Planting For Success
Walla Walla onions are typically grown from sets (small bulbs) or transplants in early spring as soon as the soil can be worked. They require full sun and loose, well-draining soil rich in organic matter.
- Space plants 4-6 inches apart in rows 12-18 inches apart to give bulbs room to expand.
- Plant them shallowly, with just the tip of the set or the base of the transplant showing above the soil.
- Consistent moisture is crucial during the bulbing phase. Water deeply when the top inch of soil is dry.
Seasonal Care For Optimal Bulbs
As the season progresses, a few key care tips will direct the plant’s energy into bulb formation.
Feed onions with a nitrogen-rich fertilizer early in the season to support top growth, but stop fertilizing once the bulbs begin to form, as excess nitrogen at this stage can hinder bulbing and storage quality. Keep the onion bed well-weeded, as competition for resources can result in smaller bulbs. Mulching can help retain moisture and suppress weeds.
Frequently Asked Questions
How Do You Know When Walla Walla Onions Are Ready To Pick?
You know Walla Walla onions are ready to pick when about a third of the green tops have naturally fallen over and turned yellow-brown. The neck (where the leaves meet the bulb) will feel soft, and the outer skin of the bulb will appear papery. This usually occurs in mid to late summer.
Can You Eat Walla Walla Onions Right After Harvest?
Yes, you can eat Walla Walla onions immediately after harvest, and they will be delicious. However, even for immediate use, letting them dry in the sun for a day will help the outer skin toughen up for easier peeling. For storage, a full 2-3 week cure is essential.
Why Are My Walla Walla Onions So Small?
Small Walla Walla onions are often the result of overcrowding, inconsistent watering, poor soil nutrition, or harvesting too early. Ensure they have adequate space, receive deep weekly watering during dry periods, and are planted in rich, loose soil. Let the tops fall over naturally before harvesting.
How Long Do Harvested Walla Walla Onions Last?
When properly cured and stored in a cool, dry, ventilated place, harvested Walla Walla onions can last for 1 to 3 months. Their high sugar and water content makes them more perishable than other storage onion varieties, so plan to use them within this timeframe.
What Is The Best Way To Store Walla Walla Sweet Onions?
The best way to store Walla Walla sweet onions is in a cool (35-50°F), dark, dry, and well-ventilated location. Place cured onions in mesh bags, wire baskets, or nylon stockings to ensure air circulation. Never store them in sealed plastic containers or bags, as this promotes rot.