When to Plant Komatsuna in USDA Zone 9a
Your June game plan for Zone 9a
June is a pivotal month for Zone 9a gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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 9a, the average last spring frost is around February 10 and the first fall frost is around December 10, giving you a growing season of approximately 303 days.
Komatsuna Planting Timeline — Zone 9a
Where Is USDA Zone 9a?
The map below highlights the states that contain Zone 9a. Click any state to see the Komatsuna planting schedule for that location.
Komatsuna Planting Calendar — Zone 9a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 13 | Jan 13 – Jan 27 |
| Transplant Outdoors | February 10 | Feb 10 – Feb 24 |
| Direct Sow | January 20 | Jan 20 – Feb 10 |
| Harvest | March 17 | Mar 17 – Apr 21 |
| Fall Sowing | October 15 | Oct 15 – Oct 29 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Direct Sow |
| February | Transplant Outdoors Direct Sow |
| March | Harvest |
| April | Harvest |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Free Zone 9a Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 9a 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
20°F to 25°F average annual minimum
Growing Season
303 days (Zone 9a average)
Planting Specifications
| Planting Depth | 0.5 inches |
| Plant Spacing | 6 inches apart |
| Row Spacing | 12 inches between rows |
Succession Planting Komatsuna in Zone 9a
Sow every 4 weeks for continuous harvest throughout the season.
Growing Tips for Komatsuna in Zone 9a
Zone 9a offers a long growing season (~303 days). You can plant Komatsuna earlier and may get multiple harvests.
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
The Gardener's Encyclopedia to Companion Planting
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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
- 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 Komatsuna in Zone 9a?
In Zone 9a, plan your Komatsuna planting around the average last frost date of February 10. Start seeds indoors around January 13. Direct sow outdoors around January 20. Transplant seedlings around February 10.
Can Komatsuna grow in Zone 9a?
Yes, Komatsuna can grow well in Zone 9a, hardy in USDA zones 2a through 11b. Zone 9a has a growing season of approximately 303 days, which is sufficient for Komatsuna (35-50 days to maturity).
When can I harvest Komatsuna in Zone 9a?
In Zone 9a, expect to harvest Komatsuna from March 17 – April 21. Komatsuna takes 35-50 days from planting to harvest.
What is the last frost date for Zone 9a?
The average last spring frost in Zone 9a is around February 10, and the first fall frost is around December 10. This gives a growing season of approximately 303 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.
Your Zone 9a Garden Planner — Free
A 22-page printable planner tailored to Zone 9a. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.