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When to Plant Rosemary in Seminole County, FL

Seminole County, Florida Zone 10a May

Your May game plan for Seminole County, Florida

May is a pivotal month for Seminole County, Florida gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 3
Avg. first frost December 21
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. It's harvest week for rosemary

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Coming up in June — start thinking about
  • First harvests: rosemary

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Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.

Seminole County, Florida is in USDA Zone 10a. The average last spring frost is February 3 and the first fall frost is December 21, giving you a growing season of approximately 321 days.

At an elevation of 260 feet, Seminole County receives approximately 53.9 inches of rainfall annually with predominantly sand soil. Summer highs average 95°F, so Rosemary may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Rosemary will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.

Seminole County, FL (Zone 10a) Year-round
321 days
Last Spring Frost February 3
321 growing days
First Fall Frost December 21
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Seminole County Soil Profile

Soil Type

Sand

Soil pH

5.2-5.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (101 days to spare)
Transplant: Jan 26 🍅 Harvest: Apr 20 – Sep 7
Recommended (50%) ✓ Fits season (90 days to spare)
Transplant: Feb 10 🍅 Harvest: May 5 – Sep 22
Safe Start (90%) ✓ Fits season (67 days to spare)
Transplant: Mar 10 🍅 Harvest: Jun 2 – Oct 20

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 Seminole County

How your county's soil matches Rosemary's growing requirements.

Soil pH

Your soil pH (5.2–5.9) is more acidic than Rosemary prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Seminole County warms quickly in spring but drains fast. Rosemary will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Rosemary.

Organic Matter

Organic matter is low (1.5%). Add 2-3 inches of compost before planting Rosemary.

How to Plant Rosemary

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

Succession Planting Rosemary

4
successive plantings in your 321-day season

Sow every 9.1 weeks. Last sowing by Jun 24 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.7″/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 Rosemary

Rosemary 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 Rosemary Needs Rainfall You Supplement Action
Jan 2.9" 0" ❄️ Dormant
Feb 1.3" 3" 0" ✅ Rainfall sufficient
Mar 1.3" 2.9" 0" ✅ Rainfall sufficient
Apr 1.3" 2.8" 0" ✅ Rainfall sufficient
May 1.3" 3.8" 0" ✅ Rainfall sufficient
Jun 1.3" 7.9" 0" ✅ Rainfall sufficient
Jul 1.3" 7.7" 0" ✅ Rainfall sufficient
Aug 1.3" 6.9" 0" ✅ Rainfall sufficient
Sep 1.3" 6.4" 0" ✅ Rainfall sufficient
Oct 1.3" 5.2" 0" ✅ Rainfall sufficient
Nov 1.3" 2.2" 0" ✅ Rainfall sufficient
Dec 1.3" 2.2" 0" ✅ Rainfall sufficient

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

Rosemary 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.

Rosemary needs ~2,762 GDD — county provides 6,842 GDD Excellent fit

Rosemary Planting Timeline — Seminole County, FL

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors February 10 Feb 10 – Feb 24
Harvest May 5 May 5 – Sep 22

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Natural rainfall sufficient

📅 Days to Maturity

80–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 10a

📆 Growing Season

321 days in Seminole County

Growing Tips for Rosemary in Seminole County

Direct sow Rosemary outdoors after February 03 in Seminole County when soil has warmed and frost danger has passed.

Sandy soil in Seminole County dries quickly — mulch Rosemary with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

General growing tips

Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rosemary in Seminole County, FL?

Seminole County is in Zone 10a with an average last frost of February 3. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Seminole County, FL?

Seminole County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is February 3 and first fall frost is December 21.

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Your Seminole County Garden Planner — Free

A 24-page printable planner built for Seminole County (Zone 10a). 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 Seminole County, FL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.