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When to plant Cosmos in Manatee County County,

Cosmos planted in Manatee County County between December 17 and January 7 matures in 90 days — well before the December 20 first frost.

When to Plant Cosmos in Manatee County, FL

Manatee County, Florida Zone 10a June

June in Manatee County, Florida — your action list

Your Manatee County, Florida garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost January 28
Avg. first frost December 20
Soil temp (4") 89°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. It's harvest week for cosmos

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

To set up a strong July, finish these tasks
  • 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.

Manatee County, Florida is in USDA Zone 10a. The average last spring frost is January 28 and the first fall frost is December 20, giving you a growing season of approximately 326 days.

At an elevation of 237 feet, Manatee County receives approximately 57.6 inches of rainfall annually with predominantly sand soil. Summer highs average 103°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
Manatee County, FL (Zone 10a) Year-round
326 days
Last Spring Frost January 28
326 growing days
First Fall Frost December 20
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Manatee County Soil Profile

Soil Type

Sand

Soil pH

5-5.9

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✓ Fits season (96 days to spare)
Start indoors: Dec 25 Transplant: Dec 11 🌸 Bloom: Feb 19 – Sep 3
Recommended (50%) ✓ Fits season (102 days to spare)
Start indoors: Dec 31 Transplant: Dec 17 🌸 Bloom: Feb 25 – Sep 9
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: Jan 31 Transplant: Jan 17 🌸 Bloom: Mar 28 – Oct 10

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 Manatee County

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

Soil pH

Your soil pH (5.0–5.9) is more acidic than Cosmos prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

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 326-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

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" 2.6" 0" ✅ Rainfall sufficient
Feb 2.2" 2.8" 0" ✅ Rainfall sufficient
Mar 2.2" 3.3" 0" ✅ Rainfall sufficient
Apr 2.2" 3" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 8.7" 0" ✅ Rainfall sufficient
Jul 2.2" 8.4" 0" ✅ Rainfall sufficient
Aug 2.2" 7.2" 0" ✅ Rainfall sufficient
Sep 2.2" 8.4" 0" ✅ Rainfall sufficient
Oct 2.2" 4.7" 0" ✅ Rainfall sufficient
Nov 2.2" 2.6" 0" ✅ Rainfall sufficient
Dec 2.2" 2.2" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Jan–Dec in Manatee 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 ~2,044 GDD — county provides 8,910 GDD Excellent fit

Cosmos Planting Timeline — Manatee County, FL

Cosmos Planting Calendar

Activity When Date Range
Start Indoors December 31 Dec 31 – Jan 14
Transplant Outdoors December 17 Dec 17 – Dec 31
Direct Sow December 17 Dec 17 – Jan 7
Bloom February 25 Feb 25 – Sep 9

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

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February Bloom
March Bloom
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
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

326 days in Manatee County

Growing Tips for Cosmos in Manatee County

Direct sow Cosmos outdoors after January 28 in Manatee County when soil has warmed and frost danger has passed.

Sandy soil in Manatee 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 103°F in Manatee 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 Manatee County, FL?

Manatee County is in Zone 10a with an average last frost of January 28. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Manatee County, FL?

Manatee County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 28 and first fall frost is December 20.

When should I plant Cosmos in Manatee County County, ?

In Manatee County County, , plant Cosmos after the last frost (around January 28) and before the first frost (around December 20). Best results when soil holds above 50°F.

What growing zone is Manatee County County, for Cosmos?

Manatee County 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 Manatee County County's climate?

Yes — Cosmos grows well in Manatee County County's temperate climate. Manatee County County averages a 327-day frost-free season, with last frost around January 28 and first frost around December 20.

🌱

Your Manatee County Garden Planner — Free

A 22-page printable planner built for Manatee 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 Manatee 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.