When to plant Edamame in Union County, IL
The best window to plant Edamame in Union County, is April 17–May 8, when soil warms to 50°F. Last frost typically hits April 10; first frost October 21.
When to Plant Edamame in Union County, IL
Top priorities for Union County, Illinois gardeners in June
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
To set up a strong July, finish these tasks
- First harvests: edamame
Edamame are soybeans harvested at the immature green stage for a sweet, nutty snack. They are high in protein and easy to grow in warm climates.
Union County, Illinois is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 21, giving you a growing season of approximately 194 days.
At an elevation of 1,017 feet, Union County receives approximately 34.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Edamame during the growing season.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7.1
Drainage
Well Drained
Edamame 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 Union County
How your county's soil matches Edamame's growing requirements.
Soil pH
Your soil pH (5.8–7.1) overlaps with Edamame's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Union County is excellent for Edamame — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Edamame will thrive.
How to Plant Edamame
Succession Planting Edamame
Sow every 8.6 weeks. Last sowing by Jul 13 to harvest before frost.
Edamame Water Budget
Monthly Watering Guide for Edamame
Edamame needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.
| Month | Edamame Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | 3.9" | 3" | 0.9" | 💧 Light watering |
| May | 3.9" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 3.9" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 3.9" | 3.9" | 0" | ✅ Rainfall sufficient |
| Aug | 3.9" | 3.6" | 0.3" | 💧 Light watering |
| Sep | 3.9" | 3.2" | 0.7" | 💧 Light watering |
| Oct | 3.9" | 2.4" | 1.5" | 💧 Light watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Union County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Edamame 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.
Edamame Planting Timeline — Union County, IL
Edamame Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 17 | Apr 17 – May 8 |
| Harvest | July 3 | Jul 3 – Aug 14 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.9"/week · Only during dry spells
📅 Days to Maturity
75–100 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
194 days in Union County
Growing Tips for Edamame in Union County
Direct sow Edamame outdoors after April 10 in Union County when soil has warmed and frost danger has passed.
Common pests for Edamame 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 is warm. Do not over-fertilize with nitrogen. Harvest when pods are plump and bright green but before they start to yellow. Steam or boil pods before eating.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Edamame in Other Locations
Frequently Asked Questions
When should I plant Edamame in Union County, IL?
Union County is in Zone 7a with an average last frost of April 10. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, IL?
Union County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 21.
When should I plant Edamame in Union County, IL?
In Union County, IL, plant Edamame after the last frost (around April 10) and before the first frost (around October 21). Best results when soil holds above 50°F.
What growing zone is Union County, IL for Edamame?
Union County sits in USDA Zone 7a. Edamame grows reliably in zones 3a through 10b, so it's a good fit here.
Can Edamame grow in Union County's climate?
Yes — Edamame grows well in Union County's temperate climate. Union County averages a 194-day frost-free season, with last frost around April 10 and first frost around October 21.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.