When to Plant Komatsuna in North Slope Borough, AK
Your May game plan for North Slope Borough, Alaska
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in North Slope Borough, Alaska.
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.
North Slope Borough, Alaska is in USDA Zone 2b. The average last spring frost is May 27 and the first fall frost is July 31, giving you a growing season of approximately 65 days.
At an elevation of 2,600 feet, North Slope Borough receives approximately 16.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 69°F, so choose short-season varieties of Komatsuna to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Komatsuna successfully. Mulch heavily to conserve soil moisture.
North Slope Borough Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.7
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 North Slope Borough
How your county's soil matches Komatsuna's growing requirements.
Soil pH
Your soil pH (4.9–6.7) is more acidic than Komatsuna prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in North Slope Borough is excellent for Komatsuna — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Komatsuna.
Organic Matter
Organic matter is excellent (5.7%) — Komatsuna will thrive.
How to Plant Komatsuna
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
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 | — | 0.7" | 0" | ❄️ Dormant |
| Feb | — | 0.6" | 0" | ❄️ Dormant |
| Mar | — | 0.6" | 0" | ❄️ Dormant |
| Apr | — | 0.5" | 0" | ❄️ Dormant |
| May | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Jun | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Jul | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Aug | — | 2.4" | 0" | ❄️ Dormant |
| Sep | — | 3.1" | 0" | ❄️ Dormant |
| Oct | — | 2.2" | 0" | ❄️ Dormant |
| Nov | — | 1.3" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Jul in North Slope Borough). 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 — North Slope Borough, AK
Komatsuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 15 | Apr 15 – Apr 29 |
| Transplant Outdoors | May 27 | May 27 – Jun 10 |
| Direct Sow | May 20 | May 20 – Jun 10 |
| Harvest | July 1 | Jul 1 – Aug 5 |
| Fall Sowing | May 8 | May 8 – May 22 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow Fall Sowing |
| June | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| 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: too_acidic
🗺️ USDA Zone
Zone 2b
📆 Growing Season
65 days in North Slope Borough
Growing Tips for Komatsuna in North Slope Borough
Common pests for Komatsuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
North Slope Borough receives only 17" of rain annually. Komatsuna needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 North Slope Borough, AK?
North Slope Borough is in Zone 2b with an average last frost of May 27. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is North Slope Borough, AK?
North Slope Borough, Alaska is in USDA Hardiness Zone 2b. The average last spring frost is May 27 and first fall frost is July 31.
Your North Slope Borough Garden Planner — Free
A 24-page printable planner built for North Slope Borough (Zone 2b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.