When to plant Cosmos in Collier County County,
Plant Cosmos in Collier County County, when soil hits 50°F — usually November 24. Continue planting through December 15 for the spring crop.
When to Plant Cosmos in Collier County, FL
June in the garden — Collier County, Florida
Here's what deserves your attention in Collier County, Florida this month. Everything below is tailored to Zone 10b and timed around your local frost dates.
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Collect cosmos at their peak
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Before July arrives, get these ready
- First harvests: cosmos
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.
Collier County, Florida is in USDA Zone 10b. The average last spring frost is January 12 and the first fall frost is April 15, giving you a growing season of approximately 93 days.
At an elevation of 185 feet, Collier County receives approximately 61.3 inches of rainfall annually with predominantly sand soil. Summer highs average 85°F, providing good warmth for Cosmos during the growing season. 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.
Collier County Soil Profile
Soil Type
Sand
Soil pH
5-6.2
Drainage
Well Drained
Soil Compatibility in Collier County
How your county's soil matches Cosmos's growing requirements.
Soil pH
Your soil pH (5.0–6.2) is more acidic than Cosmos prefers (6.0–8.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in Collier 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 (1.3%). Add 2-3 inches of compost before planting Cosmos.
How to Plant Cosmos
Cosmos Water Budget
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" | 2.8" | 0" | ✅ Rainfall sufficient |
| Feb | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 7.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 10" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 8.4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 5.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jan–Oct in Collier 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 Planting Timeline — Collier County, FL
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 15 | Dec 15 – Dec 29 |
| Transplant Outdoors | November 24 | Nov 24 – Dec 8 |
| Direct Sow | November 24 | Nov 24 – Dec 15 |
| Bloom | February 2 | Feb 2 – Aug 31 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Bloom |
| March | Bloom |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | — |
| 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 · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: too_acidic
🗺️ USDA Zone
Zone 10b
📆 Growing Season
93 days in Collier County
Growing Tips for Cosmos in Collier County
Direct sow Cosmos outdoors after January 12 in Collier County when soil has warmed and frost danger has passed.
Sandy soil in Collier County dries quickly — mulch Cosmos with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
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 →
Cosmos in Other Locations
Frequently Asked Questions
When should I plant Cosmos in Collier County, FL?
Collier County is in Zone 10b with an average last frost of January 12. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Collier County, FL?
Collier County, Florida is in USDA Hardiness Zone 10b. The average last spring frost is January 12 and first fall frost is .
When should I plant Cosmos in Collier County County, ?
In Collier County County, , plant Cosmos 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 Collier County County, for Cosmos?
Collier County County sits in USDA Zone 10b. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.
Can Cosmos grow in Collier County County's climate?
Yes — Cosmos grows well in Collier County County's temperate climate. Collier County County averages a 365-day frost-free season, with last frost around January 1 and first frost around December 31.
Your Collier County Garden Planner — Free
A 22-page printable planner built for Collier County (Zone 10b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.