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When to plant Zinnia in Monroe County County,

For Monroe County County, gardeners: plant Zinnia November 20 through December 11 once soil reads 50°F.

When to Plant Zinnia in Monroe County, FL

Monroe County, Florida Zone 11b June

What to do in June

A quick June briefing for Monroe County, Florida gardeners — what's urgent, what's next, and what can wait.

Avg. last frost January 22
Soil temp (4") 88°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Start harvesting zinnia

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

July prep starts now
  • First harvests: zinnia

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Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.

Monroe County, Florida is in USDA Zone 11b. The average last spring frost is January 22 and the first fall frost is April 15, giving you a growing season of approximately 83 days.

At an elevation of 169 feet, Monroe County receives approximately 55.6 inches of rainfall annually with predominantly sand soil. Summer highs average 93°F, providing good warmth for Zinnia during the growing season. Sandy soil warms quickly in spring — great for early planting — but Zinnia will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Zinnia root diseases.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Monroe County, FL (Zone 11b) Year-round
365 days
Last Spring Frost No frost
365 growing days
First Fall Frost No frost

Monroe County Soil Profile

Soil Type

Sand

Soil pH

4.8-5.7

Drainage

Well Drained

Soil Compatibility in Monroe County

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

Soil pH

Your soil pH (4.8–5.7) is more acidic than Zinnia prefers (5.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Zinnia.

Organic Matter

Organic matter is low (1.3%). Add 2-3 inches of compost before planting Zinnia.

How to Plant Zinnia

0.3"
Planting Depth
12"
Between Plants
18"
Between Rows

Zinnia Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 33 gal / 100 sq ft

Monthly Watering Guide for Zinnia

Zinnia 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 Zinnia Needs Rainfall You Supplement Action
Jan 2.2" 2.3" 0" ✅ Rainfall sufficient
Feb 2.2" 2.7" 0" ✅ Rainfall sufficient
Mar 2.2" 3.8" 0" ✅ Rainfall sufficient
Apr 2.2" 2.5" 0" ✅ Rainfall sufficient
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 7.1" 0" ✅ Rainfall sufficient
Jul 2.2" 8.2" 0" ✅ Rainfall sufficient
Aug 2.2" 8.7" 0" ✅ Rainfall sufficient
Sep 2.2" 7.7" 0" ✅ Rainfall sufficient
Oct 2.2" 4.8" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

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

Zinnia 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.

Zinnia needs ~1,284 GDD — county provides 7,208 GDD Excellent fit

Zinnia Planting Timeline — Monroe County, FL

Zinnia Planting Calendar

Activity When Date Range
Start Indoors December 25 Dec 25 – Jan 8
Transplant Outdoors November 20 Nov 20 – Dec 4
Direct Sow November 20 Nov 20 – Dec 11
Bloom January 29 Jan 29 – Sep 24

Plant 0.3" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 11b

📆 Growing Season

365 days in Monroe County

Growing Tips for Zinnia in Monroe County

Direct sow Zinnia outdoors after January 22 in Monroe County when soil has warmed and frost danger has passed.

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

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

General growing tips

Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zinnia in Monroe County, FL?

Monroe County is in Zone 11b with an average last frost of January 22. Plan your Zinnia planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, FL?

Monroe County, Florida is in USDA Hardiness Zone 11b. The average last spring frost is January 22 and first fall frost is .

When should I plant Zinnia in Monroe County, ?

In Monroe County, , plant Zinnia after the last frost (around January 1) and before the first frost (around December 31). Best results when soil holds above 50°F.

What growing zone is Monroe County, for Zinnia?

Monroe County sits in USDA Zone 11b. Zinnia grows reliably in zones 3a through 11b, so it's a good fit here.

Can Zinnia grow in Monroe County's climate?

Yes — Zinnia grows well in Monroe County's temperate climate. Monroe County averages a 365-day frost-free season, with last frost around January 1 and first frost around December 31.

🌱

Your Monroe County Garden Planner — Free

A 22-page printable planner built for Monroe County (Zone 11b). 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 Monroe County, FL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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