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When to Plant Valerian in Robertson County, KY

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.

Robertson County, Kentucky is in USDA Zone 6b. The average last spring frost is April 16 and the first fall frost is October 26, giving you a growing season of approximately 193 days.

At an elevation of 2,352 feet, Robertson County receives approximately 43 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Valerian during the growing season.

Robertson County, KY (Zone 6b) Moderate season
193 days
Last Spring Frost April 16
193 growing days
First Fall Frost October 26

Robertson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 16 🍅 Harvest: Aug 20 – Oct 29
Recommended (50%) ✗ May not fit
Transplant: Apr 23 🍅 Harvest: Aug 27 – Nov 5
Safe Start (90%) ✗ May not fit
Transplant: May 10 🍅 Harvest: Sep 13 – Nov 22

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.

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 132 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Valerian needs ~2,062 GDD — county provides 2,653 GDD Good fit

Valerian Planting Timeline โ€” Robertson County, KY

Valerian Planting Calendar

Activity When Date Range
Transplant Outdoors April 23 Apr 23 โ€“ May 7
Harvest August 27 Aug 27 โ€“ Nov 5

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

120โ€“180 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 6b

Growing Season

193 days

Growing Tips for Robertson 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Valerian in Robertson County, KY?

Robertson County is in Zone 6b with an average last frost of April 16. Plan your Valerian planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Robertson County, KY?

Robertson County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 16 and first fall frost is October 26.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Robertson County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

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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 Robertson County, KY. Local conditions may vary. Last updated: April 2026.