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When to plant Cosmos in Haskell County County,

In Haskell County County, plant Cosmos in spring between April 18 and May 9, once soil temps hold above 50°F. Haskell County County's last frost averages April 18, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 90 days before the first frost on October 18.

When to Plant Cosmos in Haskell County, KS

Haskell County, Kansas Zone 6b June

June to-do list for Haskell County, Kansas

June is a pivotal month for Haskell County, Kansas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 18
Avg. first frost October 18
Soil temp (4") 74°F
Watering High
Pest pressure High
Daylight 14.6 hrs
  1. Harvest cosmos as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

July 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.

Haskell County, Kansas is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 18, giving you a growing season of approximately 183 days.

At an elevation of 824 feet, Haskell County receives approximately 24.4 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Cosmos during the growing season.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Haskell County, KS (Zone 6b) Moderate season
183 days
Last Spring Frost April 18
183 growing days
First Fall Frost October 18
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Haskell County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.4

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🌸 Bloom: Jun 23 – Oct 6
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Mar 21 Transplant: Apr 18 🌸 Bloom: Jun 27 – Oct 10
Safe Start (90%) ✓ Fits season (9 days to spare)
Start indoors: Apr 5 Transplant: May 3 🌸 Bloom: Jul 12 – Oct 25

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 Haskell County

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

Soil pH

Your soil pH (6.4–7.4) is within Cosmos's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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 183-day season

Sow every 6.9 weeks. Last sowing by Jul 20 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 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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.2" 2.5" 0" ✅ Rainfall sufficient
May 2.2" 2.8" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 2.2" 0" ✅ Rainfall sufficient
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.1" 0.1" 💧 Light watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Haskell 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 ~1,031 GDD — county provides 2,516 GDD Excellent fit

Cosmos Planting Timeline — Haskell County, KS

Cosmos Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 18 Apr 18 – May 9
Bloom June 27 Jun 27 – Oct 10

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November
December
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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 6b

📆 Growing Season

183 days in Haskell County

Growing Tips for Cosmos in Haskell County

Direct sow Cosmos outdoors after April 18 in Haskell 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.

Haskell 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 Haskell County, KS?

Haskell County is in Zone 6b with an average last frost of April 18. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haskell County, KS?

Haskell County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 18.

When should I plant Cosmos in Haskell County County, ?

In Haskell County County, , plant Cosmos after the last frost (around April 18) and before the first frost (around October 18). Best results when soil holds above 50°F.

What growing zone is Haskell County County, for Cosmos?

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

Can Cosmos grow in Haskell County County's climate?

Yes — Cosmos grows well in Haskell County County's temperate climate. Haskell County County averages a 183-day frost-free season, with last frost around April 18 and first frost around October 18.

🌱

Your Haskell County Garden Planner — Free

A 22-page printable planner built for Haskell County (Zone 6b). 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 Haskell County, KS. Local conditions may vary. Last updated: June 2026.

Sources & credits

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