When to plant Cosmos in Franklin County, FL
Plant Cosmos in Franklin County after February 25; the prime window is January 28–February 18.
When to Plant Cosmos in Franklin County, FL
August in the garden — Franklin County, Florida
Your garden in Franklin County, Florida is working on a schedule, even when you're not. Here's where you should be this August.
-
Collect cosmos at their peak
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
September prep starts now
- 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.
Franklin County, Florida is in USDA Zone 9a. The average last spring frost is February 25 and the first fall frost is November 28, giving you a growing season of approximately 276 days.
At an elevation of 487 feet, Franklin County receives approximately 59.9 inches of rainfall annually with predominantly sand soil. Summer highs average 96°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.
Franklin County Soil Profile
Soil Type
Sand
Soil pH
4.9-6
Drainage
Well Drained
Cosmos Planting Risk Windows
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 Franklin County
How your county's soil matches Cosmos's growing requirements.
Soil pH
Your soil pH (4.9–6.0) is more acidic than Cosmos prefers (6.0–8.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in Franklin 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
Succession Planting Cosmos
Sow every 6.9 weeks. Last sowing by Aug 30 to harvest before frost.
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 | — | 2.6" | 0" | ❄️ Dormant |
| Feb | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 7.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 9.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 10" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 7.4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4.9" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Dec | — | 2.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Franklin 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 — Franklin County, FL
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 28 | Jan 28 – Feb 11 |
| Transplant Outdoors | January 28 | Jan 28 – Feb 11 |
| Direct Sow | January 28 | Jan 28 – Feb 18 |
| Bloom | April 8 | Apr 8 – Sep 23 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | — |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
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 9a
📆 Growing Season
276 days in Franklin County
Growing Tips for Cosmos in Franklin County
Direct sow Cosmos outdoors after February 25 in Franklin County when soil has warmed and frost danger has passed.
Sandy soil in Franklin 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 96°F in Franklin 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 →
Cosmos in Other Locations
Frequently Asked Questions
When should I plant Cosmos in Franklin County, FL?
Franklin County is in Zone 9a with an average last frost of February 25. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Franklin County, FL?
Franklin County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 25 and first fall frost is November 28.
When should I plant Cosmos in Franklin County, FL?
In Franklin County, FL, plant Cosmos after the last frost (around February 25) and before the first frost (around November 28). Best results when soil holds above 50°F.
What growing zone is Franklin County, FL for Cosmos?
Franklin County sits in USDA Zone 9a. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.
Can Cosmos grow in Franklin County's climate?
Yes — Cosmos grows well in Franklin County's temperate climate. Franklin County averages a 277-day frost-free season, with last frost around February 25 and first frost around November 28.
Your Franklin County Garden Planner — Free
A 22-page printable planner built for Franklin County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.