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When to plant Sunchoke in Fallon County, MT

In Fallon County, Sunchoke is a spring-only crop. Plant June 3–June 17 once soil hits 50°F.

When to Plant Sunchoke in Fallon County, MT

Fallon County, Montana Zone 4b August

August to-do list for Fallon County, Montana

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

Avg. last frost May 20
Avg. first frost September 20
Soil temp (4") 53°F
Watering High
Pest pressure High
Daylight 14 hrs
Before September arrives, get these ready
  • First harvests: sunchoke

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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.

Fallon County, Montana is in USDA Zone 4b. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.

At an elevation of 6,441 feet, Fallon County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Sunchoke to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Sunchoke successfully. Mulch heavily to conserve soil moisture.

Fallon County, MT (Zone 4b) Short season
123 days
Last Spring Frost May 20
123 growing days
First Fall Frost September 20

Fallon County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.3

Drainage

Well Drained

Sunchoke Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 28 🍅 Harvest: Sep 17 – Oct 22
Recommended (50%) ✗ May not fit
Transplant: Jun 3 🍅 Harvest: Sep 23 – Oct 28
Safe Start (90%) ✗ May not fit
Transplant: Jun 22 🍅 Harvest: Oct 12 – Nov 16

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 Fallon County

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

Soil pH

Your soil pH (6.2–8.3) overlaps with Sunchoke's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Sunchoke.

How to Plant Sunchoke

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

Sunchoke Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 425 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 1.3" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 1.9" 2.4" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Fallon 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 ~1,398 GDD — county provides 1,322 GDD Tight fit

Sunchoke Planting Timeline — Fallon County, MT

Sunchoke Planting Calendar

Activity When Date Range
Transplant Outdoors June 3 Jun 3 – Jun 17
Harvest September 23 Sep 23 – Oct 28

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 4b

📆 Growing Season

123 days in Fallon County

Growing Tips for Sunchoke in Fallon County

Direct sow Sunchoke outdoors after May 20 in Fallon County when soil has warmed and frost danger has passed.

Your 123.0-day growing season in Fallon 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.

Fallon County receives only 20" of rain annually. Sunchoke needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Fallon County, MT?

Fallon County is in Zone 4b with an average last frost of May 20. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fallon County, MT?

Fallon County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 20 and first fall frost is September 20.

When should I plant Sunchoke in Fallon County, MT?

In Fallon County, MT, plant Sunchoke after the last frost (around May 20) and before the first frost (around September 20). Best results when soil holds above 50°F.

What growing zone is Fallon County, MT for Sunchoke?

Fallon County sits in USDA Zone 4b. Sunchoke grows reliably in zones 3a through 9b, so it's a good fit here.

Can Sunchoke grow in Fallon County's climate?

Yes — Sunchoke grows well in Fallon County's temperate climate. Fallon County averages a 123-day frost-free season, with last frost around May 20 and first frost around September 20.

🌱

Your Fallon County Garden Planner — Free

A 22-page printable planner built for Fallon County (Zone 4b). 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 Fallon County, MT. Local conditions may vary. Last updated: August 2026.

Sources & credits

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