Blog

When to Plant Lemon Balm in St. Johns County, FL

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.

St. Johns County, Florida is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 2, giving you a growing season of approximately 296 days.

At an elevation of 57 feet, St. Johns County receives approximately 51.1 inches of rainfall annually with predominantly sand soil. Summer highs average 99ยฐF, so Lemon Balm may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Lemon Balm will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Lemon Balm root diseases.

St. Johns County, FL (Zone 9a) Year-round
296 days
Last Spring Frost February 9
296 growing days
First Fall Frost December 2

St. Johns County Soil Profile

Soil Type

Sand

Soil pH

4.9-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (188 days to spare)
Transplant: Feb 1 🍅 Harvest: Apr 5 – May 24
Recommended (50%) ✓ Fits season (177 days to spare)
Transplant: Feb 16 🍅 Harvest: Apr 20 – Jun 8
Safe Start (90%) ✓ Fits season (168 days to spare)
Transplant: Mar 18 🍅 Harvest: May 20 – Jul 8

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
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 880 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Lemon Balm needs ~1,576 GDD — county provides 7,202 GDD Excellent fit

Lemon Balm Planting Timeline โ€” St. Johns County, FL

Lemon Balm Planting Calendar

Activity When Date Range
Transplant Outdoors February 16 Feb 16 โ€“ Mar 2
Harvest April 20 Apr 20 โ€“ Jun 8

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Transplant Outdoors
March Transplant Outdoors
April Harvest
May Harvest
June Harvest
July โ€”
August โ€”
September โ€”
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 9a

Growing Season

296 days

Growing Tips for St. Johns 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 St. Johns County, FL?

St. Johns County is in Zone 9a with an average last frost of February 9. Plan your Lemon Balm planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is St. Johns County, FL?

St. Johns County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help St. Johns County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for St. Johns County, FL. Local conditions may vary. Last updated: April 2026.