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When to Plant Lavender in Ottawa County, KS

Lavender is a fragrant perennial herb with silvery foliage and purple flower spikes. It is prized for its essential oils, culinary uses, and ornamental beauty.

Ottawa County, Kansas is in USDA Zone 5b. The average last spring frost is April 14 and the first fall frost is October 23, giving you a growing season of approximately 192 days.

At an elevation of 993 feet, Ottawa County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Lavender during the growing season.

Ottawa County, KS (Zone 5b) Moderate season
192 days
Last Spring Frost April 14
192 growing days
First Fall Frost October 23

Ottawa County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Transplant: Apr 18 🍅 Harvest: Jul 18 – Oct 3
Recommended (50%) ✓ Fits season (17 days to spare)
Transplant: Apr 21 🍅 Harvest: Jul 21 – Oct 6
Safe Start (90%) ✓ Fits season (14 days to spare)
Transplant: May 4 🍅 Harvest: Aug 3 – Oct 19

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
0.5″/week
Rainfall provides
0.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Lavender needs ~1,994 GDD — county provides 2,640 GDD Excellent fit

Lavender Planting Timeline โ€” Ottawa County, KS

Lavender Planting Calendar

Activity When Date Range
Transplant Outdoors April 21 Apr 21 โ€“ May 5
Harvest July 21 Jul 21 โ€“ Oct 6

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 Harvest
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

90โ€“200 days

Soil pH

6.5 โ€“ 8

USDA Zone

Zone 5b

Growing Season

192 days

Growing Tips for Ottawa County

Plant in well-drained, sandy soil. Avoid heavy mulching around the crown. Prune after flowering but do not cut into old wood. Lavender resents wet winter conditions.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Lavender in Ottawa County, KS?

Ottawa County is in Zone 5b with an average last frost of April 14. Plan your Lavender planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ottawa County, KS?

Ottawa County, Kansas is in USDA Hardiness Zone 5b. The average last spring frost is April 14 and first fall frost is October 23.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Ottawa County gardeners in Zone 5b 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 Ottawa County, KS. Local conditions may vary. Last updated: April 2026.