When to Plant Cosmos in Emery County, UT
June in the garden — Emery County, Utah
Welcome to June in Zone 6a. These are the moves that will have the biggest impact on your growing season.
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Indoor seed-starting week for cosmos
Starting these indoors now means sturdy transplants ready the moment your soil warms up.
July prep starts now
- First harvests: cosmos
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.
Emery County, Utah is in USDA Zone 6a. The average last spring frost is May 11 and the first fall frost is October 4, giving you a growing season of approximately 146 days.
At an elevation of 7,259 feet, Emery County receives approximately 15.6 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Cosmos during the growing season. With low rainfall, drip irrigation is essential for growing Cosmos successfully. Mulch heavily to conserve soil moisture.
Emery County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.9
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 Emery County
How your county's soil matches Cosmos's growing requirements.
Soil pH
Your soil pH (6.3–7.9) is within Cosmos's preferred range (6.0–8.0).
Soil Texture
The loam soil in Emery County is excellent for Cosmos — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Cosmos.
How to Plant Cosmos
Succession Planting Cosmos
Sow every 6.9 weeks. Last sowing by Jul 06 to harvest before frost.
Cosmos Water Budget
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" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 1.7" | 0" | ❄️ Dormant |
| May | 2.2" | 2" | 0.2" | 💧 Light watering |
| Jun | 2.2" | 1.1" | 1.1" | 🚿 Regular watering |
| Jul | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Aug | 2.2" | 1.6" | 0.6" | 💧 Light watering |
| Sep | 2.2" | 1.1" | 1.1" | 🚿 Regular watering |
| Oct | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Emery 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 Planting Timeline — Emery County, UT
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 13 | Apr 13 – Apr 27 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | May 11 | May 11 – Jun 1 |
| Bloom | July 20 | Jul 20 – Oct 26 |
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 | Direct Sow |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| 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: ideal
🗺️ USDA Zone
Zone 6a
📆 Growing Season
146 days in Emery County
Growing Tips for Cosmos in Emery County
Direct sow Cosmos outdoors after May 11 in Emery 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.
Emery 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 →
Cosmos in Other Locations
Frequently Asked Questions
When should I plant Cosmos in Emery County, UT?
Emery County is in Zone 6a with an average last frost of May 11. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Emery County, UT?
Emery County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 11 and first fall frost is October 4.
Your Emery County Garden Planner — Free
A 22-page printable planner built for Emery County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.