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When to plant Lavender in Broomfield County County,

Broomfield County County's short 135-day growing season means one Lavender planting between May 28 and June 11. No fall crop in Zone 6a.

When to Plant Lavender in Broomfield County, CO

Lavender
Broomfield County, Colorado Zone 6a June

Your June planting checklist for Broomfield County, Colorado

Welcome to June in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 14
Avg. first frost September 26
Soil temp (4") 48°F
Watering Critical
Pest pressure High
Daylight 14.8 hrs
July prep starts now
  • Starting indoors: lavender

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Lavender (Lavandula angustifolia) is a fragrant Mediterranean sub-shrub prized for its silver-gray foliage and intensely aromatic purple flower spikes. A classic companion for roses and an unmatched pollinator magnet, lavender thrives in the exact conditions that challenge many plants: poor, rocky, alkaline soil with excellent drainage and full sun. English lavender is the most cold-hardy species, reliably perennial in Zones 5–9. Fresh or dried flowers are widely used in sachets, essential oils, culinary applications, and dried arrangements.

Broomfield County, Colorado is in USDA Zone 6a. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 7,037 feet, Broomfield County receives approximately 13.9 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Lavender during the growing season. With low rainfall, drip irrigation is essential for growing Lavender successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting Fragrant
Broomfield County, CO (Zone 6a) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26

Broomfield County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.2

Drainage

Well Drained

Lavender Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Feb 22 Transplant: May 17 🌸 Bloom: Jul 26 – Sep 20
Recommended (50%) ✗ May not fit
Start indoors: Mar 5 Transplant: May 28 🌸 Bloom: Aug 6 – Oct 1
Safe Start (90%) ✗ May not fit
Start indoors: Apr 1 Transplant: Jun 24 🌸 Bloom: Sep 2 – Oct 28

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 Broomfield County

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

Soil pH

Your soil pH (6.2–8.2) overlaps with Lavender's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Lavender.

How to Plant Lavender

0.5"
Planting Depth
18"
Between Plants
24"
Between Rows

Lavender Water Budget

Plant needs
0.3″/week
Rainfall provides
0.4″/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 1.1" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 1.3" 1.7" 0" ✅ Rainfall sufficient
Jun 1.3" 0.9" 0.4" 💧 Light watering
Jul 1.3" 1.3" 0" ✅ Rainfall sufficient
Aug 1.3" 1.6" 0" ✅ Rainfall sufficient
Sep 1.3" 1.1" 0.2" 💧 Light watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Broomfield 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 ~1,601 GDD — county provides 2,058 GDD Good fit

Lavender Planting Timeline — Broomfield County, CO

Lavender Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors May 28 May 28 – Jun 11
Bloom August 6 Aug 6 – Oct 1

Plant 0.5" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors
June Transplant Outdoors
July
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

135 days in Broomfield County

Growing Tips for Lavender in Broomfield County

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

General growing tips

The single most important requirement for lavender success is excellent drainage — it will rot in heavy clay or wet winter soils before cold alone kills it. Amend with coarse sand or fine gravel if needed; raised beds work well in Zones 5–6. Start from rooted cuttings or transplants rather than seed for named cultivars. Transplant after last frost when soil is reliably warm (55°F+). Avoid rich or overly moist soils. Prune lightly after each flush of bloom, but never cut into old wood below the green growth zone — it will not regenerate from leafless woody stems. In Zones 5–6, mulch lightly with gravel (not bark/organic material which traps moisture) around the crown for winter protection. Year 2+ plants develop into full, mature shrubs with the most prolific bloom.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lavender in Broomfield County, CO?

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

What planting zone is Broomfield County, CO?

Broomfield County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 14 and first fall frost is September 26.

When should I plant Lavender in Broomfield County County, ?

In Broomfield County County, , plant Lavender after the last frost (around May 14) and before the first frost (around September 26). Best results when soil holds above 50°F.

What growing zone is Broomfield County County, for Lavender?

Broomfield County County sits in USDA Zone 6a. Lavender grows reliably in zones 5a through 9b, so it's a good fit here.

Can Lavender grow in Broomfield County County's climate?

Yes — Lavender grows well in Broomfield County County's temperate climate. Broomfield County County averages a 135-day frost-free season, with last frost around May 14 and first frost around September 26.

🌱

Your Broomfield County Garden Planner — Free

A 22-page printable planner built for Broomfield 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 Broomfield County, CO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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