When to Plant Cosmos in USDA Zone 7b
Top priorities for Zone 7b gardeners in June
Your garden in Zone 7b is working on a schedule, even when you're not. Here's where you should be this June.
-
Harvest cosmos as they ripen
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Coming up in July — start thinking about
- 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.
In Zone 7b, the average last spring frost is around March 18 and the first fall frost is around November 8, giving you a growing season of approximately 235 days.
Cosmos Planting Timeline — Zone 7b
Where Is USDA Zone 7b?
The map below highlights the states that contain Zone 7b. Click any state to see the Cosmos planting schedule for that location.
Cosmos Planting Calendar — Zone 7b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 18 | Feb 18 – Mar 4 |
| Transplant Outdoors | March 11 | Mar 11 – Mar 25 |
| Direct Sow | March 11 | Mar 11 – Apr 1 |
| Bloom | May 20 | May 20 – Sep 23 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Direct Sow |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Free Zone 7b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 7b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
Days to Maturity
60–90 days
Soil pH
6 – 8
Zone Temperature Range
5°F to 10°F average annual minimum
Growing Season
235 days (Zone 7b average)
Planting Specifications
| Planting Depth | 0.3 inches |
| Plant Spacing | 12 inches apart |
| Row Spacing | 18 inches between rows |
Succession Planting Cosmos in Zone 7b
Sow every 6.9 weeks for continuous harvest throughout the season.
Growing Tips for Cosmos in Zone 7b
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
The Gardener's Encyclopedia to Companion Planting
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
- Bonus: square-foot gardening guide + printable seasonal planners
Saving Cosmos Seeds
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Cosmos in Other Zones
Cosmos by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Cosmos in Zone 7b?
In Zone 7b, plan your Cosmos planting around the average last frost date of March 18. Start seeds indoors around February 18. Direct sow outdoors around March 11. Transplant seedlings around March 11.
Can Cosmos grow in Zone 7b?
Yes, Cosmos can grow well in Zone 7b, hardy in USDA zones 2a through 11b. Zone 7b has a growing season of approximately 235 days, which is sufficient for Cosmos (60-90 days to maturity).
When can I harvest Cosmos in Zone 7b?
In Zone 7b, expect to harvest Cosmos from May 20 – September 23. Cosmos takes 60-90 days from planting to harvest.
What is the last frost date for Zone 7b?
The average last spring frost in Zone 7b is around March 18, and the first fall frost is around November 8. This gives a growing season of approximately 235 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Cosmos?
Good companion plants for Cosmos include Marigolds, Zinnias, Basil, Tomatoes. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 7b Garden Planner — Free
A 22-page printable planner tailored to Zone 7b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.