When to Plant Sunchoke in Washington County, WI
Your May game plan for Washington County, Wisconsin
Each item below is timed to Washington County, Wisconsin's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Set out sunchoke seedlings
Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.
Sunchokes (Jerusalem artichokes) are a native sunflower relative grown for their knobby, nutty-flavored tubers. They are extremely productive and nearly impossible to eradicate.
Washington County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 11, giving you a growing season of approximately 167 days.
At an elevation of 1,141 feet, Washington County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Sunchoke during the growing season.
Washington County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.7
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 Washington 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 Washington County is excellent for Sunchoke — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Sunchoke will thrive.
How to Plant Sunchoke
Plant Water Budget
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jul | 4.3" | 3.3" | 1" | 💧 Light watering |
| Aug | 4.3" | 4" | 0.3" | 💧 Light watering |
| Sep | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Oct | 4.3" | 3" | 1.3" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Washington 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 Planting Timeline — Washington County, WI
Sunchoke Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Harvest | August 31 | Aug 31 – Oct 26 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
110–150 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
167 days in Washington County
Growing Tips for Sunchoke in Washington County
Direct sow Sunchoke outdoors after April 27 in Washington 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 →
Sunchoke in Other Locations
Frequently Asked Questions
When should I plant Sunchoke in Washington County, WI?
Washington County is in Zone 5b with an average last frost of April 27. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.
What planting zone is Washington County, WI?
Washington County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 11.
Your Washington County Garden Planner — Free
A 24-page printable planner built for Washington 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.