When to plant Corn in Sioux County, IA
For Corn in Sioux County, the safe spring window opens around May 8 and closes around May 29. Last expected frost is May 1, first fall frost October 3, giving a 155-day growing season.
When to Plant Corn in Sioux County, IA
Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.
Sioux County, Iowa is in USDA Zone 5a. The average last spring frost is May 1 and the first fall frost is October 3, giving you a growing season of approximately 155 days.
At an elevation of 1,212 feet, Sioux County receives approximately 39.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Corn to ensure they mature before fall.
Sioux County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7
Drainage
Well Drained
How Much Corn to Grow
For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In Sioux County's 155-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Monthly Watering Guide for Corn
Corn needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Corn Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 3" | 0" | ❄️ Dormant |
| Apr | — | 4" | 0" | ❄️ Dormant |
| May | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4" | 0.3" | 💧 Light watering |
| Aug | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Sep | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Oct | 4.3" | 3.3" | 1" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Sioux County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Corn Planting Timeline — Sioux County, IA
Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 8 | May 8 – May 29 |
| Harvest | July 10 | Jul 10 – Sep 4 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | 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
60–100 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
155 days in Sioux County
Growing Tips for Sioux County
Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Corn in Other Locations
Frequently Asked Questions
When should I plant Corn in Sioux County, IA?
Sioux County is in Zone 5a with an average last frost of May 1. Plan your Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sioux County, IA?
Sioux County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 1 and first fall frost is October 3.
When should I plant Corn in Sioux County, IA?
In Sioux County, IA, plant Corn after the last frost (around May 1) and before the first frost (around October 3). Best results when soil holds above 50°F.
What growing zone is Sioux County, IA for Corn?
Sioux County sits in USDA Zone 5a. Corn grows reliably in zones 3a through 11b, so it's a good fit here.
Can Corn grow in Sioux County's climate?
Yes — Corn grows well in Sioux County's temperate climate. Sioux County averages a 155-day frost-free season, with last frost around May 1 and first frost around October 3.
Your Sioux County Garden Planner — Free
A 22-page printable planner built for Sioux 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.