When to Plant Valerian in Mercer County, OH
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.
Mercer County, Ohio is in USDA Zone 5b. The average last spring frost is April 25 and the first fall frost is October 17, giving you a growing season of approximately 175 days.
At an elevation of 874 feet, Mercer County receives approximately 32.7 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.
Mercer County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-6.7
Drainage
Well Drained
Plant Planting Risk Windows
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
Valerian Planting Timeline — Mercer County, OH
Valerian Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 2 | May 2 – May 16 |
| Harvest | September 5 | Sep 5 – Oct 17 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| 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
5.5 – 7
USDA Zone
Zone 5b
Growing Season
175 days
Growing Tips for Mercer 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
Valerian in Other Locations
Frequently Asked Questions
When should I plant Valerian in Mercer County, OH?
Mercer County is in Zone 5b with an average last frost of April 25. Plan your Valerian planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mercer County, OH?
Mercer County, Ohio is in USDA Hardiness Zone 5b. The average last spring frost is April 25 and first fall frost is October 17.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mercer County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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