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When to plant Sunchoke in Greene County, IL

Plant Sunchoke in Greene County during the brief April 27–May 11 window. With 191 frost-free days, fall plantings can't mature before October 21.

When to Plant Sunchoke in Greene County, IL

Greene County, Illinois Zone 6a June

June in Greene County, Illinois — your action list

We've pulled the most time-sensitive tasks for Greene County, Illinois this June and put them front and centre. Tackle them in order.

Avg. last frost April 13
Avg. first frost October 21
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 14.8 hrs

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Sunchokes (Jerusalem artichokes) are a native sunflower relative grown for their knobby, nutty-flavored tubers. They are extremely productive and nearly impossible to eradicate.

Greene County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 1,248 feet, Greene County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Sunchoke during the growing season.

Greene County, IL (Zone 6a) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Sunchoke Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Transplant: Apr 21 🍅 Harvest: Aug 11 – Oct 6
Recommended (50%) ✓ Fits season (9 days to spare)
Transplant: Apr 27 🍅 Harvest: Aug 17 – Oct 12
Safe Start (90%) ✓ Fits season (8 days to spare)
Transplant: May 9 🍅 Harvest: Aug 29 – Oct 24

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 Greene County

How your county's soil matches Sunchoke's growing requirements.

Soil pH

Your soil pH (6.1–6.7) is within Sunchoke's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Greene County is excellent for Sunchoke — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Sunchoke.

Organic Matter

Organic matter is excellent (4.5%) — Sunchoke will thrive.

How to Plant Sunchoke

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Sunchoke Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 992 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sunchoke

Sunchoke needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Sunchoke Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Greene County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sunchoke 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.

Sunchoke needs ~1,885 GDD — county provides 2,769 GDD Excellent fit

Sunchoke Planting Timeline — Greene County, IL

Sunchoke Planting Calendar

Activity When Date Range
Transplant Outdoors April 27 Apr 27 – May 11
Harvest August 17 Aug 17 – Oct 12

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June
July
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

110–150 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

191 days in Greene County

Growing Tips for Sunchoke in Greene County

Direct sow Sunchoke outdoors after April 13 in Greene County when soil has warmed and frost danger has passed.

Common pests for Sunchoke in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant tubers 4 inches deep in early spring. Contain plants with barriers as they spread aggressively. Harvest after frost or leave in ground and dig as needed through winter.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunchoke in Greene County, IL?

Greene County is in Zone 6a with an average last frost of April 13. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.

What planting zone is Greene County, IL?

Greene County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 21.

When should I plant Sunchoke in Greene County, IL?

In Greene County, IL, plant Sunchoke after the last frost (around April 13) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Greene County, IL for Sunchoke?

Greene County sits in USDA Zone 6a. Sunchoke grows reliably in zones 3a through 9b, so it's a good fit here.

Can Sunchoke grow in Greene County's climate?

Yes — Sunchoke grows well in Greene County's temperate climate. Greene County averages a 191-day frost-free season, with last frost around April 13 and first frost around October 21.

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Your Greene County Garden Planner — Free

A 22-page printable planner built for Greene County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Greene County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.