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When to Plant Lemon Thyme in Park County, CO

Park County, Colorado Zone 5b May

Top priorities for Park County, Colorado gardeners in May

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Avg. last frost June 16
Avg. first frost September 4
Soil temp (4") 34°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
Coming up in June — start thinking about
  • Transplants going out: lemon thyme

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Lemon thyme is a low-growing perennial herb with tiny, citrus-scented leaves. It combines the savory quality of thyme with a bright lemon flavor, excellent with fish and poultry.

Park County, Colorado is in USDA Zone 5b. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.

At an elevation of 7,567 feet, Park County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Lemon Thyme to ensure they mature before fall.

Park County, CO (Zone 5b) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4
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Park County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 17 🍅 Harvest: Aug 26 – Oct 28
Recommended (50%) ✗ May not fit
Transplant: Jun 23 🍅 Harvest: Sep 1 – Nov 3
Safe Start (90%) ✗ May not fit
Transplant: Jul 3 🍅 Harvest: Sep 11 – Nov 13

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 Park County

How your county's soil matches Lemon Thyme's growing requirements.

Soil pH

Your soil pH (6.2–7.6) is within Lemon Thyme's preferred range (6.0–8.0).

Soil Texture

The loam soil in Park County is excellent for Lemon Thyme — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Lemon Thyme.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Lemon Thyme.

How to Plant Lemon Thyme

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

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.2″/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 Lemon Thyme

Lemon Thyme needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Lemon Thyme Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3.1" 0" ❄️ Dormant
Jun 2.2" 1.8" 0.4" 💧 Light watering
Jul 2.2" 2.2" 0" ✅ Rainfall sufficient
Aug 2.2" 2.7" 0" ✅ Rainfall sufficient
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Lemon Thyme 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.

Lemon Thyme needs ~980 GDD — county provides 980 GDD Tight fit

Lemon Thyme Planting Timeline — Park County, CO

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors June 23 Jun 23 – Jul 7
Harvest September 1 Sep 1 – Nov 3

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

80 days in Park County

Growing Tips for Lemon Thyme in Park County

Direct sow Lemon Thyme outdoors after June 16 in Park County when soil has warmed and frost danger has passed.

Your 80.0-day growing season in Park County is tight for Lemon Thyme (70.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

Park County receives only 23" of rain annually. Lemon Thyme needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start from cuttings or divisions. Plant in well-drained soil. Trim back after flowering. Use as a fragrant ground cover or edging plant along garden paths.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Thyme in Park County, CO?

Park County is in Zone 5b with an average last frost of June 16. Plan your Lemon Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Park County, CO?

Park County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 16 and first fall frost is September 4.

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Your Park County Garden Planner — Free

A 24-page printable planner built for Park County (Zone 5b). 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 Park County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

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