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When to Plant Zinnia in Unity, OR

Baker County, Oregon Zone 6b July

Baker County, Oregon gardeners: here's your July plan

We've pulled the most time-sensitive tasks for Baker County, Oregon this July and put them front and centre. Tackle them in order.

Avg. last frost May 30
Avg. first frost September 12
Soil temp (4") 73°F
Watering Critical
Pest pressure High
Daylight 15.1 hrs
Looking ahead to August
  • First harvests: zinnia

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Zinnia (Zinnia elegans) is a fast-growing, heat-loving annual that produces bold, dahlia-like blooms from early summer until hard frost. One of the easiest flowers to grow from direct-sown seed, zinnias thrive in hot, dry conditions and are magnets for butterflies and beneficial insects. They make excellent companion plants alongside marigolds in the vegetable garden.

Unity, Oregon is in USDA Zone 6b. The average last spring frost is May 30 and the first fall frost is September 12, giving you a growing season of approximately 105 days.

At an elevation of 1,398 feet, Baker County receives approximately 16.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Zinnia during the growing season. With low rainfall, drip irrigation is essential for growing Zinnia successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Unity, OR (Zone 6b) Short season
105 days
Last Spring Frost May 30
105 growing days
First Fall Frost September 12

Unity Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Zinnia Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 21 Transplant: May 19 🌸 Bloom: Jul 28 – Nov 3
Recommended (50%) ✗ May not fit
Start indoors: May 2 Transplant: May 30 🌸 Bloom: Aug 8 – Nov 14
Safe Start (90%) ✗ May not fit
Start indoors: May 22 Transplant: Jun 19 🌸 Bloom: Aug 28 – Dec 4

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 Unity

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

Soil pH

Your soil pH (5.3–6.5) overlaps with Zinnia's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Zinnia.

Organic Matter

Organic matter is excellent (4.8%) — Zinnia will thrive.

How to Plant Zinnia

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

Zinnia Water Budget

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

Monthly Watering Guide for Zinnia

Zinnia 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 Zinnia Needs Rainfall You Supplement Action
Jan 2.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.1" 0" ❄️ Dormant
May 2.2" 1.1" 1.1" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 0.2" 2" 🚿 Regular watering
Aug 2.2" 0.3" 1.9" 🚿 Regular watering
Sep 2.2" 0.8" 1.4" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 2.5" 0" ❄️ Dormant
Dec 3.1" 0" ❄️ Dormant

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

Zinnia 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.

Zinnia needs ~942 GDD — county provides 1,522 GDD Excellent fit

Zinnia Planting Timeline — Unity, OR

Zinnia Planting Calendar

Activity When Date Range
Start Indoors May 2 May 2 – May 16
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 30 May 30 – Jun 20
Bloom August 8 Aug 8 – Nov 14

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
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 · Natural rainfall sufficient

📅 Days to Maturity

60–70 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

105 days in Baker County

Growing Tips for Zinnia in Unity

Direct sow Zinnia outdoors after May 30 in Baker County when soil has warmed and frost danger has passed.

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

Baker County receives only 17" of rain annually. Zinnia needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow after last frost when soil reaches 60°F; seeds germinate in 5-7 days. In zones 3-5 a brief indoor start (4 weeks) is worthwhile but transplant carefully — zinnias dislike root disturbance. Deadhead frequently to extend bloom. Excellent cut flower; harvesting regularly encourages branching. Avoid overhead watering to reduce powdery mildew.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

🌱

Your Baker County Garden Planner — Free

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