When to Plant Sweet Potatoes in Marion County, KS
May to-do list for Marion County, Kansas
Your garden in Marion County, Kansas is working on a schedule, even when you're not. Here's where you should be this May.
June prep starts now
- Starting indoors: sweet potatoes
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.
Marion County, Kansas is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 24, giving you a growing season of approximately 193 days.
At an elevation of 898 feet, Marion County receives approximately 26.4 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Sweet Potatoes during the growing season.
Marion County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.5
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 Marion County
How your county's soil matches Sweet Potatoes's growing requirements.
Soil pH
Your soil pH (6.2–7.5) is more alkaline than Sweet Potatoes prefers (5.5–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Marion County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.1%) — Sweet Potatoes will thrive.
How to Plant Sweet Potatoes
Plant Water Budget
Monthly Watering Guide for Sweet Potatoes
Sweet Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Sweet Potatoes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Aug | 4.3" | 3.3" | 1" | 💧 Light watering |
| Sep | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Oct | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Marion County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sweet Potatoes 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.
Sweet Potatoes Planting Timeline — Marion County, KS
Sweet Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 17 | Feb 17 – Mar 3 |
| Transplant Outdoors | April 28 | Apr 28 – May 12 |
| Direct Sow | April 21 | Apr 21 – May 12 |
| Harvest | July 28 | Jul 28 – Sep 15 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| 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
1"/week · 1-2 times/week
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 6b
📆 Growing Season
193 days in Marion County
Growing Tips for Sweet Potatoes in Marion County
Direct sow Sweet Potatoes outdoors after April 14 in Marion County when soil has warmed and frost danger has passed.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Sweet Potatoes in Other Locations
Frequently Asked Questions
When should I plant Sweet Potatoes in Marion County, KS?
Marion County is in Zone 6b with an average last frost of April 14. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marion County, KS?
Marion County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 24.
Your Marion County Garden Planner — Free
A 24-page printable planner built for Marion County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.