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When to plant Sunchoke in Phillips County, CO

Phillips County's 156-day season only supports one Sunchoke planting per year. Sow between May 18 and June 1 for the best chance at full maturity before October 7.

When to Plant Sunchoke in Phillips County, CO

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

Phillips County, Colorado is in USDA Zone 5b. The average last spring frost is May 4 and the first fall frost is October 7, giving you a growing season of approximately 156 days.

At an elevation of 5,494 feet, Phillips County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Sunchoke during the growing season.

Phillips County, CO (Zone 5b) Moderate season
156 days
Last Spring Frost May 4
156 growing days
First Fall Frost October 7

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Sunchoke Planting Timeline — Phillips County, CO

Sunchoke Planting Calendar

Activity When Date Range
Transplant Outdoors May 18 May 18 – Jun 1
Harvest September 7 Sep 7 – Nov 2

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 Harvest
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

110–150 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

156 days in Phillips County

Growing Tips for Phillips County

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 Phillips County, CO?

Phillips County is in Zone 5b with an average last frost of May 4. Plan your Sunchoke planting based on this frost date — see the calendar above for exact timing.

What planting zone is Phillips County, CO?

Phillips County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 4 and first fall frost is October 7.

When should I plant Sunchoke in Phillips County, CO?

In Phillips County, CO, plant Sunchoke after the last frost (around May 4) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Phillips County, CO for Sunchoke?

Phillips County sits in USDA Zone 5b. Sunchoke grows reliably in zones 3a through 9b, so it's a good fit here.

Can Sunchoke grow in Phillips County's climate?

Yes — Sunchoke grows well in Phillips County's temperate climate. Phillips County averages a 156-day frost-free season, with last frost around May 4 and first frost around October 7.

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Your Phillips County Garden Planner — Free

A 22-page printable planner built for Phillips 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.

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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 Phillips County, CO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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