When to Plant Cosmos in Keith County, NE
June in Keith County, Nebraska — your action list
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Keith County, Nebraska.
To set up a strong July, finish these tasks
- 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.
Keith County, Nebraska is in USDA Zone 5b. The average last spring frost is May 3 and the first fall frost is October 7, giving you a growing season of approximately 157 days.
At an elevation of 1,091 feet, Keith County receives approximately 22 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Cosmos to ensure they mature before fall.
Keith County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.5
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 Keith County
How your county's soil matches Cosmos's growing requirements.
Soil pH
Your soil pH (6.7–7.5) is within Cosmos's preferred range (6.0–8.0).
Soil Texture
The loam soil in Keith County is excellent for Cosmos — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.1%) — Cosmos will thrive.
How to Plant Cosmos
Succession Planting Cosmos
Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.
Cosmos Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Jul | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Aug | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.1" | 0.1" | 💧 Light watering |
| Oct | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Keith 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 — Keith County, NE
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Direct Sow | May 3 | May 3 – May 24 |
| Bloom | July 12 | Jul 12 – Oct 11 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| 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
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
157 days in Keith County
Growing Tips for Cosmos in Keith County
Direct sow Cosmos outdoors after May 03 in Keith County when soil has warmed and frost danger has passed.
Common pests for Cosmos in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Keith County receives only 22" of rain annually. Cosmos needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Keith County, NE?
Keith County is in Zone 5b with an average last frost of May 3. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Keith County, NE?
Keith County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is May 3 and first fall frost is October 7.
Your Keith County Garden Planner — Free
A 22-page printable planner built for Keith County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.