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When to plant Lemon Balm in Summit County, CO

Summit County's short 80-day growing season means one Lemon Balm planting between June 23 and July 7. No fall crop in Zone 5a.

When to Plant Lemon Balm in Summit County, CO

Summit County, Colorado Zone 5a June

June to-do list for Summit County, Colorado

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost June 16
Avg. first frost September 4
Soil temp (4") 45°F
Watering High
Pest pressure High
Daylight 14.8 hrs

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Lemon balm is a vigorous perennial herb with bright green, lemon-scented leaves. It makes a refreshing tea and is easy to grow but can spread aggressively.

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 Lemon Balm to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Lemon Balm successfully. Mulch heavily to conserve soil moisture.

Summit County, CO (Zone 5a) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4

Summit County Soil Profile

Soil Type

Loam

Soil pH

6.8-8

Drainage

Well Drained

Lemon Balm Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 17 🍅 Harvest: Aug 19 – Oct 7
Recommended (50%) ✗ May not fit
Transplant: Jun 23 🍅 Harvest: Aug 25 – Oct 13
Safe Start (90%) ✗ May not fit
Transplant: Jul 3 🍅 Harvest: Sep 4 – Oct 23

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 Lemon Balm's growing requirements.

Soil pH

Your soil pH (6.8–8.0) overlaps with Lemon Balm's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Lemon Balm.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Lemon Balm.

How to Plant Lemon Balm

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

Lemon Balm Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lemon Balm

Lemon Balm 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 Balm 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 2.2" 1.3" 0.9" 💧 Light watering
Jul 2.2" 1.5" 0.7" 💧 Light watering
Aug 2.2" 1.9" 0.3" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
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.

Lemon Balm 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 Balm needs ~699 GDD — county provides 860 GDD Good fit

Lemon Balm Planting Timeline — Summit County, CO

Lemon Balm Planting Calendar

Activity When Date Range
Transplant Outdoors June 23 Jun 23 – Jul 7
Harvest August 25 Aug 25 – Oct 13

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 Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

80 days in Summit County

Growing Tips for Lemon Balm in Summit County

Direct sow Lemon Balm 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 Lemon Balm (60.0-70.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Start from seed, cuttings, or divisions. Contain in pots or use barriers to prevent spreading. Harvest frequently to keep plants bushy and prevent flowering.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Balm in Summit County, CO?

Summit County is in Zone 5a with an average last frost of June 16. Plan your Lemon Balm 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.

When should I plant Lemon Balm in Summit County, CO?

In Summit County, CO, plant Lemon Balm after the last frost (around June 16) and before the first frost (around September 4). Best results when soil holds above 50°F.

What growing zone is Summit County, CO for Lemon Balm?

Summit County sits in USDA Zone 5a. Lemon Balm grows reliably in zones 3a through 9b, so it's a good fit here.

Can Lemon Balm grow in Summit County's climate?

Yes — Lemon Balm grows well in Summit County's temperate climate. Summit County averages a 80-day frost-free season, with last frost around June 16 and first frost around September 4.

🌱

Your Summit County Garden Planner — Free

A 22-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.

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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 Summit County, CO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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