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When to plant Valerian in Knox County, IL

In Knox County, Valerian is a spring-only crop. Plant April 24–May 8 once soil hits 50°F.

When to Plant Valerian in Knox County, IL

Valerian is a tall perennial herb with fragrant white or pink flower clusters, valued for its root which is used as a natural sleep aid. It attracts pollinators and earthworms.

Knox County, Illinois is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 15, giving you a growing season of approximately 181 days.

At an elevation of 1,301 feet, Knox County receives approximately 33.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Valerian to ensure they mature before fall.

Knox County, IL (Zone 5b) Moderate season
181 days
Last Spring Frost April 17
181 growing days
First Fall Frost October 15

Knox County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Valerian Planting Timeline — Knox County, IL

Valerian Planting Calendar

Activity When Date Range
Transplant Outdoors April 24 Apr 24 – May 8
Harvest August 28 Aug 28 – Oct 9

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June
July
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 5.5–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

181 days in Knox County

Growing Tips for Knox County

Start seeds indoors and transplant after last frost. Harvest roots in fall of the second year. Deadhead flowers unless you want self-seeding. Cats are attracted to valerian root.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Valerian in Knox County, IL?

Knox County is in Zone 5b with an average last frost of April 17. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.

What planting zone is Knox County, IL?

Knox County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 17 and first fall frost is October 15.

When should I plant Valerian in Knox County, IL?

In Knox County, IL, plant Valerian after the last frost (around April 17) and before the first frost (around October 15). Best results when soil holds above 50°F.

What growing zone is Knox County, IL for Valerian?

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

Can Valerian grow in Knox County's climate?

Yes — Valerian grows well in Knox County's temperate climate. Knox County averages a 181-day frost-free season, with last frost around April 17 and first frost around October 15.

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Your Knox County Garden Planner — Free

A 22-page printable planner built for Knox 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 Knox County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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