When to Plant Purslane in Sweet Grass County, MT
Purslane is a succulent edible plant rich in omega-3 fatty acids, often considered a weed but increasingly valued as a nutritious green. It has a lemony, peppery flavor.
Sweet Grass County, Montana is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 19, giving you a growing season of approximately 120 days.
At an elevation of 7,534 feet, Sweet Grass County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Purslane to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Purslane successfully. Mulch heavily to conserve soil moisture.
Sweet Grass County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.4
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 Sweet Grass County
How your county's soil matches Purslane's growing requirements.
Soil pH
Your soil pH (6.7–8.4) is more alkaline than Purslane prefers (5.5–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Sweet Grass County is excellent for Purslane — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Purslane.
How to Plant Purslane
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Purslane
Sow every 4.6 weeks. Last sowing by Jul 21 to harvest before frost.
For a dedicated fall crop, sow by Jul 11.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Purslane
Purslane needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Purslane Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | 2.2" | 2" | 0.2" | 💧 Light watering |
| Jun | 2.2" | 1" | 1.2" | 🚿 Regular watering |
| Jul | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Aug | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Sep | 2.2" | 1.2" | 1" | 💧 Light watering |
| Oct | — | 1.6" | 0" | ❄️ Dormant |
| Nov | — | 1.3" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Sweet Grass County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Purslane 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.
Purslane Planting Timeline — Sweet Grass County, MT
Purslane 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 | July 3 | Jul 3 – Aug 7 |
| Fall Sowing | July 11 | Jul 11 – Jul 25 |
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 |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
40–60 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
120 days in Sweet Grass County
Growing Tips for Purslane in Sweet Grass County
Direct sow Purslane outdoors after May 22 in Sweet Grass County when soil has warmed and frost danger has passed.
Sweet Grass County receives only 17" of rain annually. Purslane needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct sow after last frost or allow to self-seed. Purslane thrives in hot, dry conditions. Harvest stem tips regularly. Contains more omega-3 fatty acids than any other leafy green.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Purslane in Other Locations
Frequently Asked Questions
When should I plant Purslane in Sweet Grass County, MT?
Sweet Grass County is in Zone 5a with an average last frost of May 22. Plan your Purslane planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sweet Grass County, MT?
Sweet Grass County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 22 and first fall frost is September 19.
Your Sweet Grass County Garden Planner — Free
A 24-page printable planner built for Sweet Grass 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.