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When to plant Cosmos in Elk County County,

Plant Cosmos in Elk County County, when soil hits 50°F — usually April 7. Continue planting through April 28 for the spring crop.

When to Plant Cosmos in Elk County, KS

Elk County, Kansas Zone 7a June

Your June gardening checklist

Here's what deserves your attention in Elk County, Kansas this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 7
Avg. first frost October 25
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Collect cosmos at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Get ahead of July
  • 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.

Elk County, Kansas is in USDA Zone 7a. The average last spring frost is April 7 and the first fall frost is October 25, giving you a growing season of approximately 201 days.

At an elevation of 700 feet, Elk County receives approximately 30.4 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Cosmos during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Elk County, KS (Zone 7a) Long season
201 days
Last Spring Frost April 7
201 growing days
First Fall Frost October 25

Elk County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Start indoors: Mar 2 Transplant: Mar 30 🌸 Bloom: Jun 8 – Sep 28
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🌸 Bloom: Jun 16 – Oct 6
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Mar 24 Transplant: Apr 21 🌸 Bloom: Jun 30 – Oct 20

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 Elk County

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

Soil pH

Your soil pH (6.8–7.6) is within Cosmos's preferred range (6.0–8.0).

Soil Texture

The loam soil in Elk 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

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

Succession Planting Cosmos

3
successive plantings in your 201-day season

Sow every 6.9 weeks. Last sowing by Jul 27 to harvest before frost.

Cosmos Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.9" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.2" 3" 0" ✅ Rainfall sufficient
May 2.2" 4.7" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 3.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.7" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.1" 0.1" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Elk 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 ~1,312 GDD — county provides 3,517 GDD Excellent fit

Cosmos Planting Timeline — Elk County, KS

Cosmos Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 7 Apr 7 – Apr 21
Direct Sow April 7 Apr 7 – Apr 28
Bloom June 16 Jun 16 – Oct 6

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May
June Bloom
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 7a

📆 Growing Season

201 days in Elk County

Growing Tips for Cosmos in Elk County

Direct sow Cosmos outdoors after April 07 in Elk 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.

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 Elk County, KS?

Elk County is in Zone 7a with an average last frost of April 7. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Elk County, KS?

Elk County, Kansas is in USDA Hardiness Zone 7a. The average last spring frost is April 7 and first fall frost is October 25.

When should I plant Cosmos in Elk County County, ?

In Elk County County, , plant Cosmos after the last frost (around April 7) and before the first frost (around October 25). Best results when soil holds above 50°F.

What growing zone is Elk County County, for Cosmos?

Elk County County sits in USDA Zone 7a. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.

Can Cosmos grow in Elk County County's climate?

Yes — Cosmos grows well in Elk County County's temperate climate. Elk County County averages a 201-day frost-free season, with last frost around April 7 and first frost around October 25.

🌱

Your Elk County Garden Planner — Free

A 22-page printable planner built for Elk County (Zone 7a). 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 Elk County, KS. Local conditions may vary. Last updated: June 2026.

Sources & credits

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