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When to plant Cosmos in Cheyenne County, KS

Plant Cosmos in Cheyenne County, when soil hits 50°F — usually May 4. Continue planting through May 25 for the spring crop.

When to Plant Cosmos in Cheyenne County, KS

Cheyenne County, Kansas Zone 6a July

July in the garden — Cheyenne County, Kansas

Here's what deserves your attention in Cheyenne County, Kansas this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost May 4
Avg. first frost October 9
Soil temp (4") 78°F
Watering High
Pest pressure High
Daylight 14.6 hrs
  1. It's harvest week for cosmos

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

August will be here before you know it — start on
  • First harvests: cosmos

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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.

Cheyenne County, Kansas is in USDA Zone 6a. The average last spring frost is May 4 and the first fall frost is October 9, giving you a growing season of approximately 158 days.

At an elevation of 967 feet, Cheyenne County receives approximately 24.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Cosmos during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Cheyenne County, KS (Zone 6a) Moderate season
158 days
Last Spring Frost May 4
158 growing days
First Fall Frost October 9

Cheyenne County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.2

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: Apr 30 🌸 Bloom: Jul 9 – Oct 15
Recommended (50%) ✗ May not fit
Start indoors: Apr 6 Transplant: May 4 🌸 Bloom: Jul 13 – Oct 19
Safe Start (90%) ✗ May not fit
Start indoors: Apr 23 Transplant: May 21 🌸 Bloom: Jul 30 – Nov 5

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 Cheyenne County

How your county's soil matches Cosmos's growing requirements.

Soil pH

Your soil pH (6.3–7.2) is within Cosmos's preferred range (6.0–8.0).

Soil Texture

The loam soil in Cheyenne County is excellent for Cosmos — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Cosmos.

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Cosmos.

How to Plant Cosmos

0.3"
Planting Depth
12"
Between Plants
18"
Between Rows

Succession Planting Cosmos

3
successive plantings in your 158-day season

Sow every 6.9 weeks. Last sowing by Jul 11 to harvest before frost.

Cosmos Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Only during dry spells
Season total 7 gal / 100 sq ft
Drought risk

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 1.5" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 2.2" 2.6" 0" ✅ Rainfall sufficient
Jun 2.2" 1.7" 0.5" 💧 Light watering
Jul 2.2" 2.4" 0" ✅ Rainfall sufficient
Aug 2.2" 2.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Cheyenne 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 needs ~1,088 GDD — county provides 2,291 GDD Excellent fit

Cosmos Planting Timeline — Cheyenne County, KS

Cosmos Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 4 May 4 – May 18
Direct Sow May 4 May 4 – May 25
Bloom July 13 Jul 13 – Oct 19

Plant 0.3" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

MonthActivities
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 · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

158 days in Cheyenne County

Growing Tips for Cosmos in Cheyenne County

Direct sow Cosmos outdoors after May 04 in Cheyenne 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.

Cheyenne County receives only 24" 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 →

Frequently Asked Questions

When should I plant Cosmos in Cheyenne County, KS?

Cheyenne County is in Zone 6a with an average last frost of May 4. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cheyenne County, KS?

Cheyenne County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is May 4 and first fall frost is October 9.

When should I plant Cosmos in Cheyenne County, KS?

In Cheyenne County, KS, plant Cosmos after the last frost (around May 4) and before the first frost (around October 9). Best results when soil holds above 50°F.

What growing zone is Cheyenne County, KS for Cosmos?

Cheyenne County sits in USDA Zone 6a. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.

Can Cosmos grow in Cheyenne County's climate?

Yes — Cosmos grows well in Cheyenne County's temperate climate. Cheyenne County averages a 158-day frost-free season, with last frost around May 4 and first frost around October 9.

🌱

Your Cheyenne County Garden Planner — Free

A 22-page printable planner built for Cheyenne County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Cheyenne County, KS. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.