Blog

When to Plant Cosmos in Pershing County, NV

Pershing County, Nevada Zone 6b June

This month in Pershing County, Nevada

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

Avg. last frost May 23
Avg. first frost September 23
Soil temp (4") 60°F
Watering Critical
Pest pressure High
Daylight 14.9 hrs
  1. Fire up the seed-starting tray: cosmos

    These need a head start before your last frost (May 23). Sow into cells now so you're ready to transplant in a few weeks.

Instant PDF download. No spam, unsubscribe any time.

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.

Pershing County, Nevada is in USDA Zone 6b. The average last spring frost is May 23 and the first fall frost is September 23, giving you a growing season of approximately 123 days.

At an elevation of 4,541 feet, Pershing County receives approximately 16.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 100°F, so Cosmos may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Cosmos will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Cosmos successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Pershing County, NV (Zone 6b) Short season
123 days
Last Spring Frost May 23
123 growing days
First Fall Frost September 23

Pershing County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.3

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 15 Transplant: May 13 🌸 Bloom: Jul 22 – Nov 4
Recommended (50%) ✗ May not fit
Start indoors: Apr 25 Transplant: May 23 🌸 Bloom: Aug 1 – Nov 14
Safe Start (90%) ✗ May not fit
Start indoors: May 19 Transplant: Jun 16 🌸 Bloom: Aug 25 – Dec 8

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 Pershing County

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

Soil pH

Your soil pH (7.0–8.3) overlaps with Cosmos's range (6.0–8.0), though not a perfect match.

Soil Texture

Sandy soil in Pershing County warms quickly in spring but drains fast. Cosmos will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Cosmos.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Cosmos.

How to Plant Cosmos

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

Succession Planting Cosmos

2
successive plantings in your 123-day season

Sow every 6.9 weeks. Last sowing by Jun 25 to harvest before frost.

Cosmos Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 127 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 0.9" 0" ❄️ Dormant
Apr 0.6" 0" ❄️ Dormant
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.5" 1.7" 🚿 Regular watering
Jul 2.2" 3" 0" ✅ Rainfall sufficient
Aug 2.2" 3.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2.1" 0.1" 💧 Light watering
Oct 1.7" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Pershing 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 ~1,875 GDD — county provides 3,075 GDD Excellent fit

Cosmos Planting Timeline — Pershing County, NV

Cosmos Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 – May 9
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 23 May 23 – Jun 13
Bloom August 1 Aug 1 – Nov 14

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Bloom
September Bloom
October Bloom
November Bloom
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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

123 days in Pershing County

Growing Tips for Cosmos in Pershing County

Direct sow Cosmos outdoors after May 23 in Pershing County when soil has warmed and frost danger has passed.

Sandy soil in Pershing County dries quickly — mulch Cosmos with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 100°F in Pershing County, provide afternoon shade for Cosmos and water deeply in the morning.

Common pests for Cosmos in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Pershing County receives only 16" 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 Pershing County, NV?

Pershing County is in Zone 6b with an average last frost of May 23. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pershing County, NV?

Pershing County, Nevada is in USDA Hardiness Zone 6b. The average last spring frost is May 23 and first fall frost is September 23.

🌱

Your Pershing County Garden Planner — Free

A 22-page printable planner built for Pershing 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Pershing County, NV. 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.