When to Plant Komatsuna in USDA Zone 9b
Komatsuna (Japanese mustard spinach) is a versatile Asian green with glossy, dark leaves and a mild, sweet flavor. It is extremely cold-hardy and heat-tolerant.
In Zone 9b, the average last spring frost is around January 25 and the first fall frost is around December 20, giving you a growing season of approximately 329 days.
Komatsuna Planting Timeline — Zone 9b
Where Is USDA Zone 9b?
The map below highlights the states that contain Zone 9b. Click any state to see the Komatsuna planting schedule for that location.
Komatsuna Planting Calendar — Zone 9b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 28 | Dec 28 – Jan 11 |
| Transplant Outdoors | January 25 | Jan 25 – Feb 8 |
| Direct Sow | January 4 | Jan 4 – Jan 25 |
| Fall Sowing | October 25 | Oct 25 – Nov 8 |
| Harvest | March 1 | Mar 1 – Apr 5 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | Transplant Outdoors |
| March | Harvest |
| April | Harvest |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | Fall Sowing |
| December | Start Indoors |
Free Zone 9b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 9b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Partial Shade (3-6 hours)
Water
Moderate — regular watering
Days to Maturity
35–50 days
Soil pH
6 – 7.5
Zone Temperature Range
25°F to 30°F average annual minimum
Growing Season
329 days (Zone 9b average)
Planting Specifications
| Planting Depth | 0.5 inches |
| Plant Spacing | 6 inches apart |
| Row Spacing | 12 inches between rows |
Growing Tips for Zone 9b
Direct sow in spring or fall. One of the most forgiving Asian greens for all seasons. Harvest outer leaves or cut whole plants. Excellent for stir-fries, soups, or salads.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Saving Komatsuna Seeds
Recommended for Your Garden
Reduce heat stress and sun scorch in hot climates with UV-stabilized shade cloth.
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Related Plants
Komatsuna in Other Zones
Komatsuna by State
- Alabama
- Alaska
- Alberta
- Arizona
- Arkansas
- British Columbia
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Manitoba
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Brunswick
- New Hampshire
- New Jersey
- New Mexico
- New York
- Newfoundland and Labrador
- North Carolina
- North Dakota
- Northwest Territories
- Nova Scotia
- Nunavut
- Ohio
- Oklahoma
- Ontario
- Oregon
- Pennsylvania
- Prince Edward Island
- Quebec
- Rhode Island
- Saskatchewan
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
- Yukon
Frequently Asked Questions
When should I plant Komatsuna in Zone 9b?
In Zone 9b, plan your Komatsuna planting around the average last frost date of January 25. Start seeds indoors around December 28. Direct sow outdoors around January 4. Transplant seedlings around January 25.
Can Komatsuna grow in Zone 9b?
Yes, Komatsuna can grow well in Zone 9b, hardy in USDA zones 2a through 11b. Zone 9b has a growing season of approximately 329 days, which is sufficient for Komatsuna (35-50 days to maturity).
When can I harvest Komatsuna in Zone 9b?
In Zone 9b, expect to harvest Komatsuna from March 1 – April 5. Komatsuna takes 35-50 days from planting to harvest.
What is the last frost date for Zone 9b?
The average last spring frost in Zone 9b is around January 25, and the first fall frost is around December 20. This gives a growing season of approximately 329 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Komatsuna?
Good companion plants for Komatsuna include Lettuce, Spinach, Radish. These companions can help with pest control, pollination, and nutrient sharing.
Plan Your Garden with Confidence
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