When to Plant Cosmos in Thurston County, NE
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.
Thurston County, Nebraska is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 10, giving you a growing season of approximately 165 days.
At an elevation of 584 feet, Thurston County receives approximately 31.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Cosmos during the growing season.
Thurston County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Cosmos Planting Timeline — Thurston County, NE
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 31 | Mar 31 – Apr 14 |
| Transplant Outdoors | May 5 | May 5 – May 19 |
| Direct Sow | May 5 | May 5 – May 26 |
| Bloom | July 14 | Jul 14 – Oct 6 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
165 days in Thurston County
Growing Tips for Thurston County
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 Thurston County, NE?
Thurston County is in Zone 5a with an average last frost of April 28. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Thurston County, NE?
Thurston County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 10.
Your Thurston County Garden Planner — Free
A 22-page printable planner built for Thurston County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.