When to Plant Potatoes in Decatur County, IA
Decatur County, Iowa gardeners: here's your May plan
A quick May briefing for Decatur County, Iowa gardeners — what's urgent, what's next, and what can wait.
-
Time to transplant potatoes
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
Coming up in June — start thinking about
- Starting indoors: potatoes
Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.
Decatur County, Iowa is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 12, giving you a growing season of approximately 172 days.
At an elevation of 541 feet, Decatur County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Potatoes to ensure they mature before fall.
Decatur County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.3
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 Decatur County
How your county's soil matches Potatoes's growing requirements.
Soil pH
Your soil pH (6.0–7.3) is more alkaline than Potatoes prefers (5.0–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The silt loam soil in Decatur County is excellent for Potatoes — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Potatoes.
Organic Matter
Organic matter is excellent (4.2%) — Potatoes will thrive.
How to Plant Potatoes
Succession Planting Potatoes
Sow every 8 weeks. Last sowing by Jun 14 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Potatoes
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 | Potatoes Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| May | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Sep | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Decatur County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
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.
Potatoes Planting Timeline — Decatur County, IA
Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 26 | Feb 26 – Mar 12 |
| Transplant Outdoors | May 7 | May 7 – May 21 |
| Direct Sow | April 30 | Apr 30 – May 21 |
| Harvest | July 16 | Jul 16 – Sep 24 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | 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
70–120 days
🧪 Soil pH
Needs 5–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5b
📆 Growing Season
172 days in Decatur County
Growing Tips for Potatoes in Decatur County
Direct sow Potatoes outdoors after April 23 in Decatur County when soil has warmed and frost danger has passed.
Common pests for Potatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Potatoes in Other Locations
Frequently Asked Questions
When should I plant Potatoes in Decatur County, IA?
Decatur County is in Zone 5b with an average last frost of April 23. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Decatur County, IA?
Decatur County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 12.
Your Decatur County Garden Planner — Free
A 24-page printable planner built for Decatur County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.