Onion
Seed # 218
Basic Information
- Seed Number
- 218
- Seed Name
- Onion
- Variety
- Walla Walla
- Category
- Vegetable
- Plant Family
- Amaryllidaceae
- Plant Type
- Long-day sweet bulbing onion (Allium cepa)
- Planting Method
- Direct Sow or Transplant
- Seed Status
- In Seed Bank
- Created
- 2026-08-14 00:50:34
- Updated
- 2026-08-19 15:35:29
Planting Information
- Start Planting Date
- Feb 10
- Last Recommended Planting Date
- May 15
- Plantable Months
- February, March, April, May
- Indoor Start
- Feb 10 – Feb 24
- Direct Sow
- Mar 15 – Apr 15
- Transplant
- Apr 15 – May 15
- Indoor Start Weeks Before Frost
- 12 weeks
- Transplant Weeks After Frost
- Not recorded
- Germination Days
- 7–14 days
- Harvest/Maturity
- 115 days
- Succession Planting
- Not recorded
Growing Conditions
- Ideal Soil Temperature
- Not recorded
- Planting Depth
- 1/4-1/2 in
- Plant Spacing
- 3-4 in
- Row Spacing
- 12-18 in
- Thin-To Spacing
- 3-4 in
- Sun Requirements
- Full sun
- Water Needs
- Maintain consistent moisture during vegetative growth and bulb enlargement
- Soil Preference
- Fertile, loose, well-drained soil rich in organic matter
- Minimum Container Size
- 8–10+ in deep with adequate spacing
- Plant Height
- Not recorded
- Perennial/Biennial Status
- Biennial
- Container Friendly
- Yes
- Trellis/Support Needed
- No
- Frost Tolerant
- Yes
- Heat Tolerant
- No
- Drought Tolerant
- No
- Pollinator Friendly
- Yes
- Medicinal
- No
Garden Uses
Container Culinary Pollinator Seed SavingCompanion Planting
| Plant | Relationship | Notes |
|---|---|---|
| Broccoli | Good Companion | Not recorded |
| Radish | Good Companion | Not recorded |
| Radish | Good Companion | Not recorded |
| Radish | Good Companion | Not recorded |
| Radish | Good Companion | Not recorded |
| Onion | Avoid | Not recorded |
| Onion | Avoid | Not recorded |
| Onion | Avoid | Not recorded |
| Onion | Avoid | Not recorded |
| Onion | Avoid | Not recorded |
Storage
- Seed Source/Brand
- Johnny's Selected Seeds; MSU Extension
- Packet Year
- Not recorded
- Quantity Notes
- Not recorded
- Purchase Date
- Not recorded
- Expiration Year
- Not recorded
- Storage Box
- Not recorded
- Container
- Not recorded
- Envelope
- Not recorded
- Row
- Not recorded
- Slot
- Not recorded
- Storage Notes
- Not recorded
Notes
Original Planting Method: Start indoors 8–12 weeks before last frost; transplant early, or direct sow as soon as soil can be worked
Outdoor / Direct Sow / Transplant Window: Transplant/direct sow about Mar 25 – Apr 30
Germination Time: About 7–14 days
Days to Harvest / Bloom: About 125 days from spring sowing
Container Friendly: Yes, 8–10+ in deep with adequate spacing
Pollinator Friendly: Low if harvested as bulbs; second-year flowers attract many pollinators
Medicinal / Herbal Use: Culinary onion
Perennial?: Biennial botanically; usually grown as an annual bulb crop
Succession / Reusable Notes: One early sowing is usually enough; harvest when tops fall and cure bulbs before storage.
Zone 6B Notes: Spring sow/transplant is the safest approach in Zone 6B. Overwintering can be less reliable in cold Michigan winters.
Companion Plants: Carrots, beets, lettuce, cabbage-family crops and tomatoes
Avoid Planting Near / Watch Outs: Needs a long growing season. Walla Walla is a sweet onion and is not considered a long-storage onion. Avoid waterlogged soil.
Sources: Johnny's Selected Seeds: https://www.johnnyseeds.com/vegetables/onions/full-size-onions/walla-walla-sweet-onion-seed-496.html | MSU Extension: https://www.canr.msu.edu/resources/garden_planning_calendar
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Zone 6B: Walla Walla is a long-day sweet onion appropriate for northern latitudes including Southeast Michigan. Starting seed indoors early gives bulbs time to develop substantial foliage before summer bulbing.
Germination: Onions germinate slowly in cold soil and more rapidly as soil warms.
Harvest: Harvest when tops naturally fall and necks begin to dry. Cure before storage. Walla Walla is prized for sweetness more than very long storage.
Seed Saving: Allium cepa is biennial and requires overwintering/vernalization before flowering. Isolate from other flowering A. cepa onions.
Special Care: Walla Walla produces large, mild, juicy sweet bulbs and is classified as a long-day onion.
Research Source: Urban Farmer — https://www.ufseeds.com/product/walla-walla-sweet-onion-seeds---1%2F4-ounce/ONWWS-1_4-ounce.html — Allium cepa identity, 115-day maturity, full sun and Walla Walla sweet-onion identity
Research Source: University of Minnesota Extension — https://extension.umn.edu/vegetables/growing-onions — 10-12 week indoor start, direct seeding, depth, transplanting, spacing and row spacing
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