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When to Plant Sunchoke in Williams County, ND

Williams County, North Dakota Zone 4a May

What to do in May

Each item below is timed to Williams County, North Dakota's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 14
Avg. first frost September 22
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 15 hrs
  1. Set out sunchoke seedlings

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Williams County, North Dakota is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 22, giving you a growing season of approximately 131 days.

At an elevation of 947 feet, Williams County receives approximately 28.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Sunchoke to ensure they mature before fall.

Williams County, ND (Zone 4a) Short season
131 days
Last Spring Frost May 14
131 growing days
First Fall Frost September 22

Williams County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 24 🍅 Harvest: Sep 13 – Oct 18
Recommended (50%) ✗ May not fit
Transplant: May 28 🍅 Harvest: Sep 17 – Oct 22
Safe Start (90%) ✗ May not fit
Transplant: Jun 13 🍅 Harvest: Oct 3 – Nov 7

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 Williams County

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

Soil pH

Your soil pH (6.4–7.6) overlaps with Sunchoke's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Sunchoke.

How to Plant Sunchoke

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 139 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.8" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 2.1" 2.2" 🚿 Regular watering
Jul 4.3" 2.4" 1.9" 💧 Light watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 2.7" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Williams 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 ~1,690 GDD — county provides 1,703 GDD Good fit

Sunchoke Planting Timeline — Williams County, ND

Sunchoke Planting Calendar

Activity When Date Range
Transplant Outdoors May 28 May 28 – Jun 11
Harvest September 17 Sep 17 – Oct 22

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August
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: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

131 days in Williams County

Growing Tips for Sunchoke in Williams County

Direct sow Sunchoke outdoors after May 14 in Williams County when soil has warmed and frost danger has passed.

Your 131.0-day growing season in Williams County is tight for Sunchoke (110.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Williams County, ND?

Williams County is in Zone 4a with an average last frost of May 14. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.

What planting zone is Williams County, ND?

Williams County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 22.

🌱

Your Williams County Garden Planner — Free

A 24-page printable planner built for Williams County (Zone 4a). 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 Williams County, ND. Local conditions may vary. Last updated: May 2026.

Sources & credits

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