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When to Plant Lavender in Cumberland County, IL

Cumberland County, Illinois Zone 6b May

What to do in May

Each item below is timed to Cumberland County, Illinois's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 14
Avg. first frost October 17
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs

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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.

Cumberland County, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 772 feet, Cumberland County receives approximately 31.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Lavender during the growing season.

Cumberland County, IL (Zone 6b) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17

Cumberland County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 16 🍅 Harvest: Jul 16 – Oct 29
Recommended (50%) ✗ May not fit
Transplant: Apr 21 🍅 Harvest: Jul 21 – Nov 3
Safe Start (90%) ✗ May not fit
Transplant: May 5 🍅 Harvest: Aug 4 – Nov 17

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.

Soil Compatibility in Cumberland County

How your county's soil matches Lavender's growing requirements.

Soil pH

Your soil pH (6.3–7.0) overlaps with Lavender's range (6.5–8.0), though not a perfect match.

Soil Texture

The silt loam soil in Cumberland County is excellent for Lavender — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Lavender.

How to Plant Lavender

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Lavender

Lavender needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Lavender Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 1.3" 3.3" 0" ✅ Rainfall sufficient
May 1.3" 3.3" 0" ✅ Rainfall sufficient
Jun 1.3" 3.5" 0" ✅ Rainfall sufficient
Jul 1.3" 3.6" 0" ✅ Rainfall sufficient
Aug 1.3" 3" 0" ✅ Rainfall sufficient
Sep 1.3" 2.9" 0" ✅ Rainfall sufficient
Oct 1.3" 2.7" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cumberland County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Lavender Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Lavender needs ~2,102 GDD — county provides 2,697 GDD Good fit

Lavender Planting Timeline — Cumberland County, IL

Lavender Planting Calendar

Activity When Date Range
Transplant Outdoors April 21 Apr 21 – May 5
Harvest July 21 Jul 21 – Nov 3

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 Harvest
August Harvest
September Harvest
October Harvest
November Harvest
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Natural rainfall sufficient

📅 Days to Maturity

90–200 days

🧪 Soil pH

Needs 6.5–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

186 days in Cumberland County

Growing Tips for Lavender in Cumberland County

Direct sow Lavender outdoors after April 14 in Cumberland County when soil has warmed and frost danger has passed.

Your 186.0-day growing season in Cumberland County is tight for Lavender (90.0-200.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lavender in Cumberland County, IL?

Cumberland County is in Zone 6b with an average last frost of April 14. Plan your Lavender planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cumberland County, IL?

Cumberland County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 17.

🌱

Your Cumberland County Garden Planner — Free

A 24-page printable planner built for Cumberland County (Zone 6b). 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 Cumberland County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.