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When to Plant Lemon Balm in Morgan County, CO

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.

Morgan County, Colorado is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 7,673 feet, Morgan County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, 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.

Morgan County, CO (Zone 5a) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5

Morgan County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Transplant: May 9 🍅 Harvest: Jul 11 – Aug 29
Recommended (50%) ✓ Fits season (29 days to spare)
Transplant: May 17 🍅 Harvest: Jul 19 – Sep 6
Safe Start (90%) ✓ Fits season (30 days to spare)
Transplant: May 27 🍅 Harvest: Jul 29 – Sep 16

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 782 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Lemon Balm needs ~845 GDD — county provides 1,924 GDD Excellent fit

Lemon Balm Planting Timeline โ€” Morgan County, CO

Lemon Balm Planting Calendar

Activity When Date Range
Transplant Outdoors May 17 May 17 โ€“ May 31
Harvest July 19 Jul 19 โ€“ Sep 6

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“70 days

Soil pH

5.5 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

148 days

Growing Tips for Morgan County

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

Level Up Your Garden

Frequently Asked Questions

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

Morgan County is in Zone 5a with an average last frost of May 10. Plan your Lemon Balm planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Morgan County, CO?

Morgan County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Morgan County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Morgan County, CO. Local conditions may vary. Last updated: April 2026.