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When to plant Cosmos in Glades County, FL

Plant Cosmos in Glades County from December 21 to January 11 in spring. Glades County sits in USDA Zone 10a, with last frost around February 1 and first frost on December 19.

When to Plant Cosmos in Glades County, FL

Glades County, Florida Zone 10a June

This month in Glades County, Florida

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

Avg. last frost February 1
Avg. first frost December 19
Soil temp (4") 88°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Pick cosmos

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Get ahead of 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.

Glades County, Florida is in USDA Zone 10a. The average last spring frost is February 1 and the first fall frost is December 19, giving you a growing season of approximately 321 days.

At an elevation of 434 feet, Glades County receives approximately 54.3 inches of rainfall annually with predominantly sand soil. Summer highs average 101°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
Glades County, FL (Zone 10a) Year-round
321 days
Last Spring Frost February 1
321 growing days
First Fall Frost December 19

Glades County Soil Profile

Soil Type

Sand

Soil pH

5.1-6.3

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✓ Fits season (95 days to spare)
Start indoors: Dec 25 Transplant: Dec 11 🌸 Bloom: Feb 19 – Sep 3
Recommended (50%) ✓ Fits season (97 days to spare)
Start indoors: Jan 4 Transplant: Dec 21 🌸 Bloom: Mar 1 – Sep 13
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Feb 1 Transplant: Jan 18 🌸 Bloom: Mar 29 – Oct 11

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 Glades County

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

Soil pH

Your soil pH (5.1–6.3) is more acidic than Cosmos prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Glades 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 321-day season

Sow every 6.9 weeks. Last sowing by Sep 20 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 2.7" 0" ❄️ Dormant
Feb 2.2" 2.5" 0" ✅ Rainfall sufficient
Mar 2.2" 2.9" 0" ✅ Rainfall sufficient
Apr 2.2" 2.7" 0" ✅ Rainfall sufficient
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 8" 0" ✅ Rainfall sufficient
Jul 2.2" 8.3" 0" ✅ Rainfall sufficient
Aug 2.2" 7.7" 0" ✅ Rainfall sufficient
Sep 2.2" 7.2" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2.3" 0" ✅ Rainfall sufficient
Dec 2.2" 2.3" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Glades 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 ~1,931 GDD — county provides 8,291 GDD Excellent fit

Cosmos Planting Timeline — Glades County, FL

Cosmos Planting Calendar

Activity When Date Range
Start Indoors January 4 Jan 4 – Jan 18
Transplant Outdoors December 21 Dec 21 – Jan 4
Direct Sow December 21 Dec 21 – Jan 11
Bloom March 1 Mar 1 – Sep 13

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

Month-by-Month Timeline

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

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

321 days in Glades County

Growing Tips for Cosmos in Glades County

Direct sow Cosmos outdoors after February 01 in Glades County when soil has warmed and frost danger has passed.

Sandy soil in Glades 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 101°F in Glades 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 Glades County, FL?

Glades County is in Zone 10a with an average last frost of February 1. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Glades County, FL?

Glades County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is February 1 and first fall frost is December 19.

When should I plant Cosmos in Glades County, FL?

In Glades County, FL, plant Cosmos after the last frost (around February 1) and before the first frost (around December 19). Best results when soil holds above 50°F.

What growing zone is Glades County, FL for Cosmos?

Glades 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 Glades County's climate?

Yes — Cosmos grows well in Glades County's temperate climate. Glades County averages a 322-day frost-free season, with last frost around February 1 and first frost around December 19.

🌱

Your Glades County Garden Planner — Free

A 22-page printable planner built for Glades 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 Glades 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.