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When to Plant Lavender in Mineral County, MT

Mineral County, Montana Zone 6a May

Your May planting checklist for Mineral County, Montana

We've pulled the most time-sensitive tasks for Mineral County, Montana this May and put them front and centre. Tackle them in order.

Avg. last frost May 30
Avg. first frost September 20
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
Get ahead of June
  • Transplants going out: lavender

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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.

Mineral County, Montana is in USDA Zone 6a. The average last spring frost is May 30 and the first fall frost is September 20, giving you a growing season of approximately 113 days.

At an elevation of 5,389 feet, Mineral County receives approximately 12.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Lavender to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Lavender successfully. Mulch heavily to conserve soil moisture.

Mineral County, MT (Zone 6a) Short season
113 days
Last Spring Frost May 30
113 growing days
First Fall Frost September 20
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Mineral County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 21 🍅 Harvest: Aug 20 – Dec 3
Recommended (50%) ✗ May not fit
Transplant: Jun 6 🍅 Harvest: Sep 5 – Dec 19
Safe Start (90%) ✓ Fits season (275 days to spare)
Transplant: Jun 26 🍅 Harvest: Sep 25 – Jan 8

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 Mineral County

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

Soil pH

Your soil pH (6.7–7.7) is within Lavender's preferred range (6.5–8.0).

Soil Texture

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

Drainage

Drainage is adequate for Lavender.

Organic Matter

Organic matter is moderate (2.4%). 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
0.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 0.9" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.1" 0" ❄️ Dormant
May 1.3" 1.6" 0" ✅ Rainfall sufficient
Jun 1.3" 0.9" 0.4" 💧 Light watering
Jul 1.3" 1.2" 0.1" 💧 Light watering
Aug 1.3" 1.3" 0" ✅ Rainfall sufficient
Sep 1.3" 1.1" 0.2" 💧 Light watering
Oct 1.2" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Mineral 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 ~1,885 GDD — county provides 1,469 GDD May not mature

Lavender Planting Timeline — Mineral County, MT

Lavender Planting Calendar

Activity When Date Range
Transplant Outdoors June 6 Jun 6 – Jun 20
Harvest September 5 Sep 5 – Dec 19

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6a

📆 Growing Season

113 days in Mineral County

Growing Tips for Lavender in Mineral County

Direct sow Lavender outdoors after May 30 in Mineral County when soil has warmed and frost danger has passed.

Your 113.0-day growing season in Mineral 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 Mineral County, MT?

Mineral County is in Zone 6a with an average last frost of May 30. Plan your Lavender planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mineral County, MT?

Mineral County, Montana is in USDA Hardiness Zone 6a. The average last spring frost is May 30 and first fall frost is September 20.

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Your Mineral County Garden Planner — Free

A 24-page printable planner built for Mineral County (Zone 6a). 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 Mineral County, MT. 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.