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When to plant Cosmos in Brevard County County,

Plant Cosmos in Brevard County County from December 8 to December 29 in spring. Brevard County County sits in USDA Zone 10a, with last frost around January 19 and first frost on December 20.

When to Plant Cosmos in Brevard County, FL

Brevard County, Florida Zone 10a June

June in the garden — Brevard County, Florida

We've pulled the most time-sensitive tasks for Brevard County, Florida this June and put them front and centre. Tackle them in order.

Avg. last frost January 19
Avg. first frost December 20
Soil temp (4") 88°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Start harvesting cosmos

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

A few tasks this June that'll pay off in July
  • First harvests: cosmos

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Cosmos (Cosmos bipinnatus) is an airy, feathery-foliaged cottage garden annual from Mexico that thrives on neglect. It produces delicate daisy-like blooms in shades of pink, white, and magenta from midsummer until frost. Cosmos is a prolific self-sower — once established in a garden it often returns year after year without replanting. Excellent habitat plant for beneficial insects.

Brevard County, Florida is in USDA Zone 10a. The average last spring frost is January 19 and the first fall frost is December 20, giving you a growing season of approximately 335 days.

At an elevation of 491 feet, Brevard County receives approximately 52.7 inches of rainfall annually with predominantly sand soil. Summer highs average 104°F, so Cosmos may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Cosmos will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cosmos root diseases.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Brevard County, FL (Zone 10a) Year-round
335 days
Last Spring Frost January 19
335 growing days
First Fall Frost December 20
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Brevard County Soil Profile

Soil Type

Sand

Soil pH

4.8-5.9

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✓ Fits season (114 days to spare)
Start indoors: Dec 16 Transplant: Dec 2 🌸 Bloom: Feb 10 – Aug 25
Recommended (50%) ✓ Fits season (111 days to spare)
Start indoors: Dec 22 Transplant: Dec 8 🌸 Bloom: Feb 16 – Aug 31
Safe Start (90%) ✓ Fits season (86 days to spare)
Start indoors: Jan 20 Transplant: Jan 6 🌸 Bloom: Mar 17 – Sep 29

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 Brevard County

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

Soil pH

Your soil pH (4.8–5.9) is more acidic than Cosmos prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Cosmos.

Organic Matter

Organic matter is low (1.6%). Add 2-3 inches of compost before planting Cosmos.

How to Plant Cosmos

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

Succession Planting Cosmos

6
successive plantings in your 335-day season

Sow every 6.9 weeks. Last sowing by Sep 21 to harvest before frost.

Cosmos Water Budget

Plant needs
0.5″/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 Cosmos

Cosmos 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 Cosmos Needs Rainfall You Supplement Action
Jan 2.2" 2.2" 0" ✅ Rainfall sufficient
Feb 2.2" 3.1" 0" ✅ Rainfall sufficient
Mar 2.2" 3.5" 0" ✅ Rainfall sufficient
Apr 2.2" 2.5" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 7.5" 0" ✅ Rainfall sufficient
Jul 2.2" 6.6" 0" ✅ Rainfall sufficient
Aug 2.2" 6.8" 0" ✅ Rainfall sufficient
Sep 2.2" 7.6" 0" ✅ Rainfall sufficient
Oct 2.2" 5" 0" ✅ Rainfall sufficient
Nov 2.2" 1.9" 0.3" 💧 Light watering
Dec 2.2" 2.3" 0" ✅ Rainfall sufficient

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

Cosmos 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.

Cosmos needs ~2,100 GDD — county provides 9,408 GDD Excellent fit

Cosmos Planting Timeline — Brevard County, FL

Cosmos Planting Calendar

Activity When Date Range
Start Indoors December 22 Dec 22 – Jan 5
Transplant Outdoors December 8 Dec 8 – Dec 22
Direct Sow December 8 Dec 8 – Dec 29
Bloom February 16 Feb 16 – Aug 31

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 10a

📆 Growing Season

335 days in Brevard County

Growing Tips for Cosmos in Brevard County

Direct sow Cosmos outdoors after January 19 in Brevard County when soil has warmed and frost danger has passed.

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

With summer highs reaching 104°F in Brevard County, provide afternoon shade for Cosmos and water deeply in the morning.

Common pests for Cosmos 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; cosmos germinates readily at 65-80°F in 7-10 days. Avoid rich soil — excess fertility produces lush foliage at the expense of blooms. Cosmos tolerates poor, dry soil exceptionally well. Pinch seedlings at 8 inches to encourage branching. Self-sows freely; allow some seed heads to mature and drop for a no-fuss perennial effect in warm climates.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cosmos in Brevard County, FL?

Brevard County is in Zone 10a with an average last frost of January 19. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brevard County, FL?

Brevard County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 19 and first fall frost is December 20.

When should I plant Cosmos in Brevard County, ?

In Brevard County, , plant Cosmos after the last frost (around January 19) and before the first frost (around December 20). Best results when soil holds above 50°F.

What growing zone is Brevard County, for Cosmos?

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

Can Cosmos grow in Brevard County's climate?

Yes — Cosmos grows well in Brevard County's temperate climate. Brevard County averages a 336-day frost-free season, with last frost around January 19 and first frost around December 20.

🌱

Your Brevard County Garden Planner — Free

A 22-page printable planner built for Brevard 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 Brevard 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.