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When to Plant Borage in Clark County, WI

Borage is a self-seeding annual herb with star-shaped blue flowers that attract pollinators. Its leaves have a cucumber-like flavor and the flowers are edible.

Clark County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.

At an elevation of 850 feet, Clark County receives approximately 39.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Borage to ensure they mature before fall.

Clark County, WI (Zone 4b) Short season
140 days
Last Spring Frost May 13
140 growing days
First Fall Frost September 30

Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Borage Planting Timeline — Clark County, WI

Borage Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors May 6 May 6 – May 20
Direct Sow May 6 May 6 – May 27
Harvest July 1 Jul 1 – Aug 19
Fall Sowing July 8 Jul 8 – Jul 22

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June
July Fall Sowing Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 4b

📆 Growing Season

140 days in Clark County

Growing Tips for Clark County

Direct sow in spring as borage does not transplant well. Allow some plants to go to seed for next year. Young leaves are best; older leaves become bristly.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Borage in Clark County, WI?

Clark County is in Zone 4b with an average last frost of May 13. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, WI?

Clark County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 13 and first fall frost is September 30.

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Your Clark County Garden Planner — Free

A 22-page printable planner built for Clark 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 Clark County, WI. 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.