When to Plant Tatsoi in Roosevelt County, MT
May to-do list for Roosevelt County, Montana
A quick May briefing for Roosevelt County, Montana gardeners — what's urgent, what's next, and what can wait.
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Plant out tatsoi
Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.
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Outdoor sowing time: tatsoi
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
Before June arrives, get these ready
- Starting indoors: tatsoi
- First harvests: tatsoi
- Fall sowing: 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.
Roosevelt County, Montana is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is September 18, giving you a growing season of approximately 124 days.
At an elevation of 7,123 feet, Roosevelt County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 78°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.
Roosevelt County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.7
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 Roosevelt County
How your county's soil matches Tatsoi's growing requirements.
Soil pH
Your soil pH (6.7–7.7) overlaps with Tatsoi's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Roosevelt 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 12 weeks before your first frost date for a fall harvest.
Succession Planting Tatsoi
Sow every 4 weeks. Last sowing by Jul 30 to harvest before frost.
For a dedicated fall crop, sow by Jun 26.
Plant Water Budget
Water stress score is 8/10 — 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.7" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | 4.3" | 2.3" | 2" | 💧 Light watering |
| Jun | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jul | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Aug | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Sep | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Roosevelt 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 — Roosevelt County, MT
Tatsoi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 17 | May 17 – May 31 |
| Direct Sow | May 10 | May 10 – May 31 |
| Harvest | June 21 | Jun 21 – Jul 26 |
| Fall Sowing | June 26 | Jun 26 – Jul 10 |
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 |
| June | Fall Sowing 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 4a
📆 Growing Season
124 days in Roosevelt County
Growing Tips for Tatsoi in Roosevelt County
Direct sow Tatsoi outdoors after May 17 in Roosevelt 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.
Roosevelt County receives only 20" 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 Roosevelt County, MT?
Roosevelt County is in Zone 4a with an average last frost of May 17. Plan your Tatsoi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Roosevelt County, MT?
Roosevelt County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is September 18.
Your Roosevelt County Garden Planner — Free
A 24-page printable planner built for Roosevelt County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.