Purple Top Walla Walla
Allium cepa 'Purple Top Walla Walla'
The sweet, mild onion that made Walla Walla, Washington famous. This beloved heirloom variety produces large, flattened bulbs with purple-tinged skin and crisp white flesh so sweet they can be eaten like apples. Perfect for those who want to grow their own version of this premium market onion.
Harvest
125-300d
Days to harvest
Sun
Full sun
Zones
5–10
USDA hardiness
Height
12-18 inches
Planting Timeline
Showing dates for Purple Top Walla Walla in USDA Zone 7
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Purple Top Walla Walla · Zones 5–10
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | — | — | May – June | December – October |
| Zone 4 | — | — | April – June | November – October |
| Zone 5 | — | — | April – May | November – November |
| Zone 6 | — | — | April – May | November – November |
| Zone 7 | — | — | March – May | October – November |
| Zone 8 | — | — | March – April | October – December |
| Zone 9 | — | — | February – March | September – December |
| Zone 10 | — | — | January – March | August – December |
Complete Growing Guide
Light: Full sun (6 or more hours of direct sunlight a day). Soil: High Organic Matter, Loam (Silt), Sand. Soil pH: Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 1 ft. 0 in. - 1 ft. 6 in.. Spread: 0 ft. 6 in. - 1 ft. 0 in.. Spacing: Less than 12 inches, 12 inches-3 feet. Maintenance: Medium. Regions: Coastal, Mountains, Piedmont.
Harvesting
Flowers wither and convert to bulblets
Type: Capsule.
Harvest time: Summer
Bloom time: Summer
Storage & Preservation
Fresh Purple Top Walla Walla onions require immediate curing after harvest. Spread them in a single layer in a warm, dry, well-ventilated area for 2-3 weeks until necks are completely dry and papery. Unlike storage onions, Walla Wallas have high water content and low sulfur, giving them only 1-3 months storage life even under ideal conditions.
Store cured bulbs in mesh bags or ventilated boxes at 32-35°F with low humidity, checking regularly and using any with soft spots immediately. For longer preservation, slice and freeze them for up to 8 months, or caramelize and freeze in portions. They also pickle beautifully – their mild, sweet flavor makes excellent quick pickles or pickled onion rings. Dehydrating works well too, though you'll lose some of the characteristic sweetness that makes this variety special.
History & Origin
The Purple Top Walla Walla onion originated in Corsica, France, where French soldier Pete Pieri discovered the sweet variety in the late 1800s. Pieri brought seeds back to Walla Walla Valley, Washington around 1900, where the region's unique climate and volcanic soil transformed this already mild onion into something extraordinary. The combination of cold winters, hot dry summers, and low-sulfur soil reduced the onion's pungency while concentrating its sugars.
Local Italian immigrants, particularly the Pieri and other families, began growing these onions commercially in the early 1900s. By the 1980s, Walla Walla onions had gained such a reputation for sweetness that they received protection as a trademarked name – only onions grown in specific counties of Washington and Oregon can legally be called 'Walla Walla' onions. This heirloom variety helped establish the region's agricultural identity and remains one of America's most celebrated specialty onions, often called the 'champagne of onions' for their premium quality and limited growing region.
Advantages
- +Disease resistance: Black Walnut, Deer, Rabbits
Considerations
- -Toxic: Low severity
Companion Plants
Plant Together
Carrots
Onions repel carrot fly while carrots help break up soil for onion bulbs
Tomatoes
Onions deter aphids, spider mites, and hornworms from tomato plants
Brassicas (Cabbage, Broccoli)
Onions repel cabbage worms, aphids, and flea beetles
Lettuce
Onions provide natural pest deterrent while lettuce doesn't compete for space
Peppers
Onions help repel aphids and other soft-bodied insects that damage peppers
Strawberries
Onions deter slugs, aphids, and other pests that commonly attack strawberry plants
Roses
Onions help repel aphids, thrips, and may reduce black spot disease
Marigolds
Both plants repel nematodes and various garden pests when grown together
Keep Apart
Beans
Onions can inhibit nitrogen fixation in legumes and stunt their growth
Peas
Allelopathic compounds from onions interfere with pea plant development
Asparagus
Onions can inhibit asparagus growth and reduce spear production
Sage
Both plants compete for similar nutrients and can inhibit each other's growth
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #170000)
Pests & Disease Resistance
Resistance
Moderate resistance to pink root, susceptible to downy mildew and thrips damage
Common Pests
Onion thrips, onion maggot, cutworms
Diseases
Downy mildew, purple blotch, neck rot, pink root