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When to plant Marigolds in Pinellas County, FL

The best window to plant Marigolds in Pinellas County, is December 21–January 11, when soil warms to 50°F. Last frost typically hits January 25; first frost December 16.

When to Plant Marigolds in Pinellas County, FL

Pinellas County, Florida Zone 10a August

Top priorities for Pinellas County, Florida gardeners in August

Welcome to August in Zone 10a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost January 25
Avg. first frost December 16
Soil temp (4") 96°F
Watering Low
Pest pressure High
Daylight 13 hrs
  1. Harvest marigolds as they ripen

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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Marigolds (Tagetes patula) are warm-season annuals beloved for their cheerful orange, yellow, and red blooms — and for their well-documented ability to repel pest nematodes in vegetable beds. Easy from seed, drought-tolerant once established, and bloom from early summer until the first hard frost.

Pinellas County, Florida is in USDA Zone 10a. The average last spring frost is January 25 and the first fall frost is December 16, giving you a growing season of approximately 325 days.

At an elevation of 246 feet, Pinellas County receives approximately 58.1 inches of rainfall annually with predominantly sand soil. Summer highs average 102°F, so Marigolds may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Marigolds will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Marigolds root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Pinellas County, FL (Zone 10a) Year-round
325 days
Last Spring Frost January 25
325 growing days
First Fall Frost December 16

Pinellas County Soil Profile

Soil Type

Sand

Soil pH

5.1-6.2

Drainage

Well Drained

Marigolds Planting Risk Windows

Early Start (70% safe) ✓ Fits season (115 days to spare)
Start indoors: Dec 15 Transplant: Dec 15 🌸 Bloom: Feb 9 – Aug 17
Recommended (50%) ✓ Fits season (115 days to spare)
Start indoors: Dec 21 Transplant: Dec 21 🌸 Bloom: Feb 15 – Aug 23
Safe Start (90%) ✓ Fits season (89 days to spare)
Start indoors: Jan 24 Transplant: Jan 24 🌸 Bloom: Mar 21 – Sep 26

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 Pinellas County

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

Soil pH

Your soil pH (5.1–6.2) is more acidic than Marigolds prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Marigolds.

Organic Matter

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

How to Plant Marigolds

0.3"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Marigolds

7
successive plantings in your 325-day season

Sow every 5.7 weeks. Last sowing by Oct 07 to harvest before frost.

Marigolds Water Budget

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

Monthly Watering Guide for Marigolds

Marigolds 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 Marigolds Needs Rainfall You Supplement Action
Jan 2.2" 2.9" 0" ✅ Rainfall sufficient
Feb 2.2" 3.2" 0" ✅ Rainfall sufficient
Mar 2.2" 3.7" 0" ✅ Rainfall sufficient
Apr 2.2" 2.4" 0" ✅ Rainfall sufficient
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 7.6" 0" ✅ Rainfall sufficient
Jul 2.2" 8.5" 0" ✅ Rainfall sufficient
Aug 2.2" 8.7" 0" ✅ Rainfall sufficient
Sep 2.2" 7.1" 0" ✅ Rainfall sufficient
Oct 2.2" 5.3" 0" ✅ Rainfall sufficient
Nov 2.2" 2.5" 0" ✅ Rainfall sufficient
Dec 2.2" 2.6" 0" ✅ Rainfall sufficient

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

Marigolds 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.

Marigolds needs ~1,590 GDD — county provides 8,639 GDD Excellent fit

Marigolds Planting Timeline — Pinellas County, FL

Marigolds Planting Calendar

Activity When Date Range
Start Indoors December 21 Dec 21 – Jan 4
Transplant Outdoors December 21 Dec 21 – Jan 4
Direct Sow December 21 Dec 21 – Jan 11
Bloom February 15 Feb 15 – Aug 23

Plant 0.3" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors Direct Sow
February Bloom
March Bloom
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September
October
November
December Start Indoors Transplant Outdoors Direct Sow

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 10a

📆 Growing Season

325 days in Pinellas County

Growing Tips for Marigolds in Pinellas County

Direct sow Marigolds outdoors after January 25 in Pinellas County when soil has warmed and frost danger has passed.

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

With summer highs reaching 102°F in Pinellas County, provide afternoon shade for Marigolds and water deeply in the morning.

Common pests for Marigolds in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

With 58" of annual rainfall in Pinellas County, ensure good drainage for Marigolds — excess moisture can promote root rot and fungal diseases.

General growing tips

Direct-sow after last frost or start indoors 4-6 weeks earlier. Deadhead spent blooms to keep new flowers coming. French marigolds (T. patula) are the most reliable nematode repellents — plant a band around vegetable beds. Tolerate poor soil but bloom best with monthly compost.

Companion Planting

Good Companions

Avoid Planting Near

  • Beans
  • Cabbage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Marigolds Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower heads dry on plant. Pull dried petals to reveal seeds.
Storage Store in envelopes; viable 3 years at 35°F, under 50% humidity.

Very easy to save. Seeds are the long, thin, dark pieces inside the dried flower head.

Frequently Asked Questions

When should I plant Marigolds in Pinellas County, FL?

Pinellas County is in Zone 10a with an average last frost of January 25. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pinellas County, FL?

Pinellas County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 25 and first fall frost is December 16.

When should I plant Marigolds in Pinellas County, FL?

In Pinellas County, FL, plant Marigolds after the last frost (around January 25) and before the first frost (around December 16). Best results when soil holds above 50°F.

What growing zone is Pinellas County, FL for Marigolds?

Pinellas County sits in USDA Zone 10a. Marigolds grows reliably in zones 2a through 11b, so it's a good fit here.

Can Marigolds grow in Pinellas County's climate?

Yes — Marigolds grows well in Pinellas County's temperate climate. Pinellas County averages a 326-day frost-free season, with last frost around January 25 and first frost around December 16.

🌱

Your Pinellas County Garden Planner — Free

A 22-page printable planner built for Pinellas 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 Pinellas County, FL. Local conditions may vary. Last updated: August 2026.

Sources & credits

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