When to plant Komatsuna in Stephenson County, IL
Stephenson County's spring Komatsuna window runs April 9 through April 30. time plantings around the expected last-frost window for best survival. A second sowing from August 4 to August 18 extends the harvest into fall.
When to Plant Komatsuna in Stephenson County, IL
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.
Stephenson County, Illinois is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 13, giving you a growing season of approximately 173 days.
At an elevation of 1,345 feet, Stephenson County receives approximately 36.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Komatsuna during the growing season.
Stephenson County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.1
Drainage
Well Drained
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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.3" | 1" | 💧 Light watering |
| May | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4" | 0.3" | 💧 Light watering |
| Jul | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Aug | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Sep | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Oct | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Stephenson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Komatsuna Planting Timeline — Stephenson County, IL
Komatsuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 19 | Mar 19 – Apr 2 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 9 | Apr 9 – Apr 30 |
| Harvest | May 28 | May 28 – Jul 2 |
| Fall Sowing | August 4 | Aug 4 – Aug 18 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
173 days in Stephenson County
Growing Tips for Stephenson County
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 Stephenson County, IL?
Stephenson County is in Zone 5a with an average last frost of April 23. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Stephenson County, IL?
Stephenson County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 13.
When should I plant Komatsuna in Stephenson County, IL?
In Stephenson County, IL, plant Komatsuna after the last frost (around April 23) and before the first frost (around October 13). Best results when soil holds above 50°F.
What growing zone is Stephenson County, IL for Komatsuna?
Stephenson County sits in USDA Zone 5a. Komatsuna grows reliably in zones 2a through 11b, so it's a good fit here.
Can Komatsuna grow in Stephenson County's climate?
Yes — Komatsuna grows well in Stephenson County's temperate climate. Stephenson County averages a 173-day frost-free season, with last frost around April 23 and first frost around October 13.
Your Stephenson County Garden Planner — Free
A 22-page printable planner built for Stephenson County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.