When to Plant Sweet Potatoes in Jo Daviess County, IL
Your May planting checklist for Jo Daviess County, Illinois
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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Move sweet potatoes into the garden
Frost risk is low now in Jo Daviess County, Illinois. If you've been covering beds overnight, you can stop.
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Direct-sow sweet potatoes
Mark the row. Birds and stray feet both have opinions about unmarked beds.
A few tasks this May that'll pay off in June
- 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.
Jo Daviess County, Illinois is in USDA Zone 5a. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.
At an elevation of 501 feet, Jo Daviess County receives approximately 35.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Sweet Potatoes during the growing season.
Jo Daviess County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.3
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 Jo Daviess County
How your county's soil matches Sweet Potatoes's growing requirements.
Soil pH
Your soil pH (5.9–7.3) is more alkaline than Sweet Potatoes prefers (5.5–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The silt loam soil in Jo Daviess County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — 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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Aug | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Sep | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Jo Daviess 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 — Jo Daviess County, IL
Sweet Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | May 8 | May 8 – May 22 |
| Direct Sow | May 1 | May 1 – May 22 |
| Harvest | August 7 | Aug 7 – Sep 25 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
170 days in Jo Daviess County
Growing Tips for Sweet Potatoes in Jo Daviess County
Direct sow Sweet Potatoes outdoors after April 24 in Jo Daviess 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 Jo Daviess County, IL?
Jo Daviess County is in Zone 5a with an average last frost of April 24. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jo Daviess County, IL?
Jo Daviess County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 24 and first fall frost is October 11.
Your Jo Daviess County Garden Planner — Free
A 24-page printable planner built for Jo Daviess 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.