When to Plant Sweet Potatoes in Lincoln County, MT
Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.
Lincoln County, Montana is in USDA Zone 5a. The average last spring frost is May 16 and the first fall frost is September 23, giving you a growing season of approximately 130 days.
At an elevation of 6,794 feet, Lincoln County receives approximately 18.1 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Sweet Potatoes during the growing season. With low rainfall, drip irrigation is essential for growing Sweet Potatoes successfully. Mulch heavily to conserve soil moisture.
Lincoln County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.7
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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Sweet Potatoes Planting Timeline — Lincoln County, MT
Sweet Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | May 30 | May 30 – Jun 13 |
| Direct Sow | May 23 | May 23 – Jun 13 |
| Harvest | August 29 | Aug 29 – Oct 17 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
90–120 days
Soil pH
5.5 – 6.5
USDA Zone
Zone 5a
Growing Season
130 days
Growing Tips for Lincoln County
Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Sweet Potatoes in Other Locations
Frequently Asked Questions
When should I plant Sweet Potatoes in Lincoln County, MT?
Lincoln County is in Zone 5a with an average last frost of May 16. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lincoln County, MT?
Lincoln County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 16 and first fall frost is September 23.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Lincoln County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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