When to Plant Onion in USDA Zone 8a
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
In Zone 8a, the average last spring frost is around March 8 and the first fall frost is around November 18, giving you a growing season of approximately 255 days.
Onion Planting Timeline — Zone 8a
Where Is USDA Zone 8a?
The map below highlights the states that contain Zone 8a. Click any state to see the Onion planting schedule for that location.
Onion Planting Calendar — Zone 8a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 1 | Feb 1 – Feb 15 |
| Transplant Outdoors | March 8 | Mar 8 – Mar 22 |
| Direct Sow | February 22 | Feb 22 – Mar 15 |
| Harvest | June 7 | Jun 7 – Jul 26 |
| Fall Sowing | September 9 | Sep 9 – Sep 23 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Free Zone 8a Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 8a with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
Days to Maturity
90–120 days
Soil pH
6 – 7
Zone Temperature Range
10°F to 15°F average annual minimum
Growing Season
255 days (Zone 8a average)
Planting Specifications
| Planting Depth | 1 inches |
| Plant Spacing | 6 inches apart |
| Row Spacing | 12 inches between rows |
Growing Tips for Onion in Zone 8a
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Saving Onion Seeds
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Onion in Other Zones
Onion by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Onion in Zone 8a?
In Zone 8a, plan your Onion planting around the average last frost date of March 8. Start seeds indoors around February 1. Direct sow outdoors around February 22. Transplant seedlings around March 8.
Can Onion grow in Zone 8a?
Yes, Onion can grow well in Zone 8a, hardy in USDA zones 3a through 10b. Zone 8a has a growing season of approximately 255 days, which is sufficient for Onion (90-120 days to maturity).
When can I harvest Onion in Zone 8a?
In Zone 8a, expect to harvest Onion from June 7 – July 26. Onion takes 90-120 days from planting to harvest.
What is the last frost date for Zone 8a?
The average last spring frost in Zone 8a is around March 8, and the first fall frost is around November 18. This gives a growing season of approximately 255 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Onion?
Good companion plants for Onion include Carrots, Lettuce, Beets, Cabbage. These companions can help with pest control, pollination, and nutrient sharing.
Plan Your Garden with Confidence
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