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When to Plant Celosia in Malheur County, OR

Malheur County, Oregon Zone 6b August

Your August game plan for Malheur County, Oregon

August rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Malheur County, Oregon.

Avg. last frost May 18
Avg. first frost September 29
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 13.8 hrs
  1. Harvest celosia as they ripen

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

To set up a strong September, finish these tasks
  • First harvests: celosia

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Celosia (Celosia argentea) encompasses the vivid cockscomb (cristata) and feathery plumed (plumosa) types that explode with color in summer heat. Drought-tolerant and disease-resistant, they thrive in the hottest parts of the season and produce long-lasting blooms both in the garden and as cut or dried flowers. A reliable filler in sunny annual beds.

Malheur County, Oregon is in USDA Zone 6b. The average last spring frost is May 18 and the first fall frost is September 29, giving you a growing season of approximately 134 days.

At an elevation of 2,676 feet, Malheur County receives approximately 17.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Celosia during the growing season. With low rainfall, drip irrigation is essential for growing Celosia successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Malheur County, OR (Zone 6b) Short season
134 days
Last Spring Frost May 18
134 growing days
First Fall Frost September 29

Malheur County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Celosia Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 27 Transplant: May 8 🌸 Bloom: Jul 10 – Oct 30
Recommended (50%) ✗ May not fit
Start indoors: Apr 13 Transplant: May 25 🌸 Bloom: Jul 27 – Nov 16
Safe Start (90%) ✗ May not fit
Start indoors: May 8 Transplant: Jun 19 🌸 Bloom: Aug 21 – Dec 11

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 Malheur County

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

Soil pH

Your soil pH (5.4–6.3) is more acidic than Celosia prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Malheur County is excellent for Celosia — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Celosia.

Organic Matter

Organic matter is excellent (5.6%) — Celosia will thrive.

How to Plant Celosia

0.1"
Planting Depth
9"
Between Plants
12"
Between Rows

Succession Planting Celosia

2
successive plantings in your 134-day season

Sow every 6.9 weeks. Last sowing by Jul 01 to harvest before frost.

Celosia 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 121 gal / 100 sq ft

Monthly Watering Guide for Celosia

Celosia 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 Celosia Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 2.2" 0.9" 1.3" 🚿 Regular watering
Jun 2.2" 0.7" 1.5" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.3" 1.9" 🚿 Regular watering
Sep 2.2" 0.8" 1.4" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Malheur County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Celosia 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.

Celosia needs ~1,312 GDD — county provides 2,345 GDD Excellent fit

Celosia Planting Timeline — Malheur County, OR

Celosia Planting Calendar

Activity When Date Range
Start Indoors April 13 Apr 13 – Apr 27
Transplant Outdoors May 25 May 25 – Jun 8
Direct Sow May 25 May 25 – Jun 15
Bloom July 27 Jul 27 – Nov 16

Plant 0.1" deep · 9" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Bloom
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 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

134 days in Malheur County

Growing Tips for Celosia in Malheur County

Direct sow Celosia outdoors after May 18 in Malheur County when soil has warmed and frost danger has passed.

Malheur County receives only 18" of rain annually. Celosia needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 4–6 weeks before last frost, or direct-sow after soil warms above 60°F. Does not transplant well from large pots — sow in small cells or direct-sow. Needs full sun and warm soil; cold stress causes stunting. Pinch first bloom to encourage branching. Water at the base; wet foliage encourages fungal issues. Excellent dried flower — harvest before seeds set for the best color retention.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celosia in Malheur County, OR?

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

What planting zone is Malheur County, OR?

Malheur County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 18 and first fall frost is September 29.

🌱

Your Malheur County Garden Planner — Free

A 22-page printable planner built for Malheur 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 Malheur County, OR. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.