When to plant Soybeans in Linn County, IA
Plant Soybeans in Linn County from May 2 to May 23 in spring. Linn County sits in USDA Zone 5a, with last frost around April 25 and first frost on October 11.
When to Plant Soybeans in Linn County, IA
Your June game plan for Linn County, Iowa
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Linn County, Iowa.
Get ahead of July
- First harvests: soybeans
Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.
Linn County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 11, giving you a growing season of approximately 169 days.
At an elevation of 938 feet, Linn County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Soybeans to ensure they mature before fall.
Linn County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-7.2
Drainage
Well Drained
Soybeans 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 Linn County
How your county's soil matches Soybeans's growing requirements.
Soil pH
Your soil pH (5.7–7.2) overlaps with Soybeans's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Linn County is excellent for Soybeans — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Soybeans.
Organic Matter
Organic matter is excellent (4.5%) — Soybeans will thrive.
How to Plant Soybeans
Succession Planting Soybeans
Sow every 9.1 weeks. Last sowing by Jun 13 to harvest before frost.
Soybeans Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Soybeans
Soybeans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Soybeans Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.3" | 1" | 💧 Light watering |
| May | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jul | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Aug | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Oct | 4.3" | 3" | 1.3" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Linn County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Soybeans 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.
Soybeans Planting Timeline — Linn County, IA
Soybeans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 2 | May 2 – May 23 |
| Harvest | July 25 | Jul 25 – Sep 19 |
Plant 1" deep · 15" apart · Rows 24" 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
1"/week · 1-2 times/week
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
169 days in Linn County
Growing Tips for Soybeans in Linn County
Direct sow Soybeans outdoors after April 25 in Linn County when soil has warmed and frost danger has passed.
Common pests for Soybeans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Soybeans in Other Locations
Frequently Asked Questions
When should I plant Soybeans in Linn County, IA?
Linn County is in Zone 5a with an average last frost of April 25. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.
What planting zone is Linn County, IA?
Linn County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 11.
When should I plant Soybeans in Linn County, IA?
In Linn County, IA, plant Soybeans after the last frost (around April 25) and before the first frost (around October 11). Best results when soil holds above 50°F.
What growing zone is Linn County, IA for Soybeans?
Linn County sits in USDA Zone 5a. Soybeans grows reliably in zones 3a through 10b, so it's a good fit here.
Can Soybeans grow in Linn County's climate?
Yes — Soybeans grows well in Linn County's temperate climate. Linn County averages a 169-day frost-free season, with last frost around April 25 and first frost around October 11.
Your Linn County Garden Planner — Free
A 22-page printable planner built for Linn 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.