When to Plant Thyme in Summit County, CO
This month in Summit County, Colorado
May is a pivotal month for Summit County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.
June will be here before you know it — start on
- Transplants going out: thyme
Thyme is a low-growing perennial herb with tiny, aromatic leaves and a warm, earthy flavor. It is one of the most versatile culinary and medicinal herbs.
Summit County, Colorado is in USDA Zone 5a. 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 7,005 feet, Summit County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Thyme to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Thyme successfully. Mulch heavily to conserve soil moisture.
Summit County Soil Profile
Soil Type
Loam
Soil pH
6.8-8
Drainage
Well Drained
Plant Planting Risk Windows
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 Summit County
How your county's soil matches Thyme's growing requirements.
Soil pH
Your soil pH (6.8–8.0) is within Thyme's preferred range (6.0–8.0).
Soil Texture
The loam soil in Summit County is excellent for Thyme — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Thyme.
Organic Matter
Organic matter is moderate (2.1%). Annual compost additions will help Thyme.
How to Plant Thyme
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Thyme
Thyme 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 | Thyme Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 1.7" | 0" | ❄️ Dormant |
| May | — | 1.8" | 0" | ❄️ Dormant |
| Jun | 1.3" | 1.3" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 1.5" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 1.9" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 1.3" | 0" | ✅ Rainfall sufficient |
| Oct | — | 1.6" | 0" | ❄️ Dormant |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Summit County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
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.
Thyme Planting Timeline — Summit County, CO
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
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | Transplant Outdoors |
| August | — |
| 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
70–90 days
🧪 Soil pH
Needs 6–8 · Your soil: ideal
🗺️ USDA Zone
Zone 5a
📆 Growing Season
80 days in Summit County
Growing Tips for Thyme in Summit County
Direct sow Thyme outdoors after June 16 in Summit County when soil has warmed and frost danger has passed.
Your 80.0-day growing season in Summit County is tight for Thyme (70.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Start from seed, cuttings, or divisions. Plant in well-drained, lean soil. Prune lightly after flowering. Replace plants every 3-4 years when they become woody.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Thyme in Other Locations
Frequently Asked Questions
When should I plant Thyme in Summit County, CO?
Summit County is in Zone 5a with an average last frost of June 16. Plan your Thyme planting based on this frost date — see the calendar above for exact timing.
What planting zone is Summit County, CO?
Summit County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 16 and first fall frost is September 4.
Your Summit County Garden Planner — Free
A 24-page printable planner built for Summit County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.