When to Plant Tatsoi in Stillwater County, MT
May in the garden — Stillwater County, Montana
Each item below is timed to Stillwater County, Montana's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Move tatsoi into the garden
Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.
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Put tatsoi seeds straight in the ground
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
To set up a strong June, finish these tasks
- Starting indoors: tatsoi
- First harvests: tatsoi
Tatsoi is a compact Asian green forming beautiful rosettes of dark, spoon-shaped leaves with a mild mustard flavor. It is extremely cold-hardy and versatile.
Stillwater County, Montana is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 22, giving you a growing season of approximately 123 days.
At an elevation of 6,319 feet, Stillwater County receives approximately 16.6 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Tatsoi to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Tatsoi successfully. Mulch heavily to conserve soil moisture.
Stillwater County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.8
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 Stillwater County
How your county's soil matches Tatsoi's growing requirements.
Soil pH
Your soil pH (6.3–7.8) overlaps with Tatsoi's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Stillwater County is excellent for Tatsoi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Tatsoi.
How to Plant Tatsoi
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Tatsoi
Sow every 4 weeks. Last sowing by Aug 03 to harvest before frost.
For a dedicated fall crop, sow by Jul 14.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Tatsoi
Tatsoi needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Tatsoi Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 1.8" | 0" | ❄️ Dormant |
| May | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Jun | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Jul | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Aug | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Sep | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Oct | — | 1.4" | 0" | ❄️ Dormant |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Stillwater County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Tatsoi 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.
Tatsoi Planting Timeline — Stillwater County, MT
Tatsoi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 17 | Apr 17 – May 1 |
| Transplant Outdoors | May 22 | May 22 – Jun 5 |
| Direct Sow | May 8 | May 8 – May 29 |
| Harvest | June 26 | Jun 26 – Jul 31 |
| Fall Sowing | July 14 | Jul 14 – Jul 28 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Harvest |
| July | Fall Sowing Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
123 days in Stillwater County
Growing Tips for Tatsoi in Stillwater County
Direct sow Tatsoi outdoors after May 22 in Stillwater County when soil has warmed and frost danger has passed.
Common pests for Tatsoi in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
Stillwater County receives only 17" of rain annually. Tatsoi needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct sow in spring or fall. Tatsoi tolerates frost down to 15F. Harvest outer leaves or cut whole rosettes. Excellent in salads, stir-fries, or lightly wilted.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Tatsoi in Other Locations
Frequently Asked Questions
When should I plant Tatsoi in Stillwater County, MT?
Stillwater County is in Zone 5a with an average last frost of May 22. Plan your Tatsoi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Stillwater County, MT?
Stillwater County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 22 and first fall frost is September 22.
Your Stillwater County Garden Planner — Free
A 24-page printable planner built for Stillwater 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.