When to Plant Onion in USDA Zone 6b
April in the garden — Zone 6b
Your garden in Zone 6b is working on a schedule, even when you're not. Here's where you should be this April.
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Move onion from tray to bed
Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.
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Plant onion from seed, right in the garden
Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.
A few tasks this April that'll pay off in May
- Starting indoors: onion
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 6b, the average last spring frost is around April 3 and the first fall frost is around October 25, giving you a growing season of approximately 205 days.
Onion Planting Timeline — Zone 6b
Where Is USDA Zone 6b?
The map below highlights the states that contain Zone 6b. Click any state to see the Onion planting schedule for that location.
Onion Planting Calendar — Zone 6b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | April 3 | Apr 3 – Apr 17 |
| Direct Sow | March 20 | Mar 20 – Apr 10 |
| Harvest | July 3 | Jul 3 – Aug 21 |
| Fall Sowing | August 16 | Aug 16 – Aug 30 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Free Zone 6b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 6b 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
°F to °F average annual minimum
Growing Season
205 days (Zone average)
Planting Specifications
| Planting Depth | 1 inches |
| Plant Spacing | 6 inches apart |
| Row Spacing | 12 inches between rows |
Growing Tips for Onion in Zone
Zone has a short growing season (~205 days). Start Onion indoors early and use season-extension techniques like row covers and cold frames.
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
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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 6b?
In Zone 6b, plan your Onion planting around the average last frost date of April 3. Start seeds indoors around February 27. Direct sow outdoors around March 20. Transplant seedlings around April 3.
Can Onion grow in Zone 6b?
Yes, Onion can grow well in Zone 6b, hardy in USDA zones 3a through 10b. Zone 6b has a growing season of approximately 205 days, which is sufficient for Onion (90-120 days to maturity).
When can I harvest Onion in Zone 6b?
In Zone 6b, expect to harvest Onion from July 3 – August 21. Onion takes 90-120 days from planting to harvest.
What is the last frost date for Zone 6b?
The average last spring frost in Zone 6b is around April 3, and the first fall frost is around October 25. This gives a growing season of approximately 205 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.
Your Free Printable Garden Planner
A 24-page printable planner tailored to your zone. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.