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When to plant Cosmos in Nome Census Area, AK

Nome Census Area's short 91-day growing season means one Cosmos planting between June 10 and July 1. No fall crop in Zone 3b.

When to Plant Cosmos in Nome Census Area, AK

Nome Census Area, Alaska Zone 3b July

July to-do list for Nome Census Area, Alaska

July is a pivotal month for Nome Census Area, Alaska gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 3
Avg. first frost September 2
Soil temp (4") 61°F
Watering Low
Pest pressure Moderate
Daylight 19.4 hrs
  1. Indoor seed-starting week for cosmos

    These need a head start before your last frost (June 3). Sow into cells now so you're ready to transplant in a few weeks.

Get ahead of August
  • 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.

Nome Census Area, Alaska is in USDA Zone 3b. The average last spring frost is June 3 and the first fall frost is September 2, giving you a growing season of approximately 91 days.

At an elevation of 2,593 feet, Nome Census Area receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 61°F, so choose short-season varieties of Cosmos to ensure they mature before fall.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Nome Census Area, AK (Zone 3b) Very short season
91 days
Last Spring Frost June 3
91 growing days
First Fall Frost September 2

Nome Census Area Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.7

Drainage

Well Drained

Cosmos Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 3 Transplant: Jun 7 🌸 Bloom: Aug 16 – Oct 25
Recommended (50%) ✗ May not fit
Start indoors: May 6 Transplant: Jun 10 🌸 Bloom: Aug 19 – Oct 28
Safe Start (90%) ✗ May not fit
Start indoors: May 15 Transplant: Jun 19 🌸 Bloom: Aug 28 – Nov 6

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 Nome Census Area

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

Soil pH

Your soil pH (5.0–6.7) is more acidic than Cosmos prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Nome Census Area is excellent for Cosmos — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Cosmos prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is excellent (6.2%) — Cosmos will thrive.

How to Plant Cosmos

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

Cosmos Water Budget

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

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 2" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 1.8" 0" ❄️ Dormant
Jun 2.2" 3.2" 0" ✅ Rainfall sufficient
Jul 2.2" 5.2" 0" ✅ Rainfall sufficient
Aug 2.2" 6.1" 0" ✅ Rainfall sufficient
Sep 2.2" 6.5" 0" ✅ Rainfall sufficient
Oct 4.8" 0" ❄️ Dormant
Nov 3.2" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Nome Census Area). 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 ~0 GDD — county provides 0 GDD May not mature

Cosmos Planting Timeline — Nome Census Area, AK

Cosmos Planting Calendar

Activity When Date Range
Start Indoors May 6 May 6 – May 20
Transplant Outdoors June 10 Jun 10 – Jun 24
Direct Sow June 10 Jun 10 – Jul 1
Bloom August 19 Aug 19 – Oct 28

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Start Indoors
June Transplant Outdoors Direct Sow
July Direct Sow
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: too_acidic

🗺️ USDA Zone

Zone 3b

📆 Growing Season

91 days in Nome Census Area

Growing Tips for Cosmos in Nome Census Area

Direct sow Cosmos outdoors after June 03 in Nome Census Area when soil has warmed and frost danger has passed.

Your 91.0-day growing season in Nome Census Area is tight for Cosmos (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Nome Census Area, AK?

Nome Census Area is in Zone 3b with an average last frost of June 3. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.

What planting zone is Nome Census Area, AK?

Nome Census Area, Alaska is in USDA Hardiness Zone 3b. The average last spring frost is June 3 and first fall frost is September 2.

When should I plant Cosmos in Nome Census Area, AK?

In Nome Census Area, AK, plant Cosmos after the last frost (around June 3) and before the first frost (around September 2). Best results when soil holds above 50°F.

What growing zone is Nome Census Area, AK for Cosmos?

Nome Census Area sits in USDA Zone 3b. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.

Can Cosmos grow in Nome Census Area's climate?

Yes — Cosmos grows well in Nome Census Area's temperate climate. Nome Census Area averages a 91-day frost-free season, with last frost around June 3 and first frost around September 2.

🌱

Your Nome Census Area Garden Planner — Free

A 22-page printable planner built for Nome Census Area (Zone 3b). 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 Nome Census Area, AK. 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.