When to Plant Komatsuna in Smyth County, VA
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.
Smyth County, Virginia is in USDA Zone 6b. The average last spring frost is May 2 and the first fall frost is October 12, giving you a growing season of approximately 163 days.
At an elevation of 375 feet, Smyth County receives approximately 51.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Komatsuna during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Komatsuna root diseases.
Smyth County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.8
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Smyth County
How your county's soil matches Komatsuna's growing requirements.
Soil pH
Your soil pH (5.3–6.8) overlaps with Komatsuna's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Smyth County is excellent for Komatsuna — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.5%). Annual compost additions will help Komatsuna.
How to Plant Komatsuna
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Komatsuna
Sow every 4 weeks. Last sowing by Aug 23 to harvest before frost.
For a dedicated fall crop, sow by Aug 03.
Plant Water Budget
Monthly Watering Guide for Komatsuna
Komatsuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Komatsuna Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.9" | 0" | ❄️ Dormant |
| Feb | — | 3.9" | 0" | ❄️ Dormant |
| Mar | — | 4.6" | 0" | ❄️ Dormant |
| Apr | — | 4.3" | 0" | ❄️ Dormant |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jul | 4.3" | 5.4" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 5.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Oct | 4.3" | 3.3" | 1" | 💧 Light watering |
| Nov | — | 3.7" | 0" | ❄️ Dormant |
| Dec | — | 4.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Smyth County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Komatsuna Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Komatsuna Planting Timeline — Smyth County, VA
Komatsuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 28 | Mar 28 – Apr 11 |
| Transplant Outdoors | May 2 | May 2 – May 16 |
| Direct Sow | April 18 | Apr 18 – May 9 |
| Harvest | June 6 | Jun 6 – Jul 11 |
| Fall Sowing | August 3 | Aug 3 – Aug 17 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
163 days in Smyth County
Growing Tips for Komatsuna in Smyth County
Direct sow Komatsuna outdoors after May 02 in Smyth County when soil has warmed and frost danger has passed.
Your generous 163.0-day season in Smyth County allows multiple plantings of Komatsuna. Sow every 17.0 days for continuous harvest.
Common pests for Komatsuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Komatsuna in Other Locations
Frequently Asked Questions
When should I plant Komatsuna in Smyth County, VA?
Smyth County is in Zone 6b with an average last frost of May 2. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Smyth County, VA?
Smyth County, Virginia is in USDA Hardiness Zone 6b. The average last spring frost is May 2 and first fall frost is October 12.
Plan Your Garden with Confidence
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