When to Plant Sweet Potatoes in Randolph County, IL
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.
Randolph County, Illinois is in USDA Zone 6a. The average last spring frost is April 11 and the first fall frost is October 20, giving you a growing season of approximately 192 days.
At an elevation of 501 feet, Randolph County receives approximately 32.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Sweet Potatoes during the growing season.
Randolph County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.8
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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Sweet Potatoes Planting Timeline — Randolph County, IL
Sweet Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 14 | Feb 14 – Feb 28 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 18 | Apr 18 – May 9 |
| Harvest | July 25 | Jul 25 – Sep 12 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| 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 6a
Growing Season
192 days
Growing Tips for Randolph 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 Randolph County, IL?
Randolph County is in Zone 6a with an average last frost of April 11. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Randolph County, IL?
Randolph County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 11 and first fall frost is October 20.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Randolph County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.