When to plant Cosmos in Dillingham Census Area County,
Plant Cosmos in Dillingham Census Area County, between May 8 and May 29 — the only viable window. Zone 4b's short season (128 frost-free days) rules out a fall crop.
When to Plant Cosmos in Dillingham Census Area, AK
June in Dillingham Census Area, Alaska — your action list
Welcome to June in Zone 4b. These are the moves that will have the biggest impact on your growing season.
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.
Dillingham Census Area, Alaska is in USDA Zone 4b. The average last spring frost is May 1 and the first fall frost is September 6, giving you a growing season of approximately 128 days.
At an elevation of 410 feet, Dillingham Census Area receives approximately 54 inches of rainfall annually with predominantly silt loam soil. Summer highs average 60°F, so choose short-season varieties of Cosmos to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cosmos root diseases.
Dillingham Census Area Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.2
Drainage
Well Drained
Cosmos Planting Risk Windows
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 Dillingham Census Area
How your county's soil matches Cosmos's growing requirements.
Soil pH
Your soil pH (5.0–6.2) is more acidic than Cosmos prefers (6.0–8.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Dillingham 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 (6.6%) — Cosmos will thrive.
How to Plant Cosmos
Cosmos Water Budget
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 | — | 2.6" | 0" | ❄️ Dormant |
| Feb | — | 2.4" | 0" | ❄️ Dormant |
| Mar | — | 2.2" | 0" | ❄️ Dormant |
| Apr | — | 1.8" | 0" | ❄️ Dormant |
| May | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 7.3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 8.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 9.5" | 0" | ✅ Rainfall sufficient |
| Oct | — | 6.5" | 0" | ❄️ Dormant |
| Nov | — | 4.2" | 0" | ❄️ Dormant |
| Dec | — | 3.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Dillingham 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 Planting Timeline — Dillingham Census Area, AK
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 3 | Apr 3 – Apr 17 |
| Transplant Outdoors | May 8 | May 8 – May 22 |
| Direct Sow | May 8 | May 8 – May 29 |
| Bloom | July 17 | Jul 17 – Oct 9 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: too_acidic
🗺️ USDA Zone
Zone 4b
📆 Growing Season
128 days in Dillingham Census Area
Growing Tips for Cosmos in Dillingham Census Area
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 →
Cosmos in Other Locations
Frequently Asked Questions
When should I plant Cosmos in Dillingham Census Area, AK?
Dillingham Census Area is in Zone 4b with an average last frost of May 1. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Dillingham Census Area, AK?
Dillingham Census Area, Alaska is in USDA Hardiness Zone 4b. The average last spring frost is May 1 and first fall frost is September 6.
When should I plant Cosmos in Dillingham Census Area County, ?
In Dillingham Census Area County, , plant Cosmos after the last frost (around May 1) and before the first frost (around September 6). Best results when soil holds above 50°F.
What growing zone is Dillingham Census Area County, for Cosmos?
Dillingham Census Area County sits in USDA Zone 4b. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.
Can Cosmos grow in Dillingham Census Area County's climate?
Yes — Cosmos grows well in Dillingham Census Area County's temperate climate. Dillingham Census Area County averages a 128-day frost-free season, with last frost around May 1 and first frost around September 6.
Your Dillingham Census Area Garden Planner — Free
A 22-page printable planner built for Dillingham Census Area (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.