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When to Plant Dianthus in Multnomah County, OR

Multnomah County, Oregon Zone 9a June

Your June planting checklist for Multnomah County, Oregon

Your Multnomah County, Oregon garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 14
Avg. first frost October 27
Soil temp (4") 80°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Sow dianthus in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Bring in the dianthus

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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China pinks (Dianthus chinensis) are a reliable cool-season annual offering fringed blooms with a spicy-sweet clove fragrance. They perform best in the cool temperatures of spring and fall, providing vivid color in beds and borders when summer annuals haven't kicked in yet. In warmer zones they are grown as fall–winter–spring annuals. The compact mounding habit and clean foliage make them excellent edging and container plants.

Multnomah County, Oregon is in USDA Zone 9a. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.

At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Dianthus to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Multnomah County, OR (Zone 9a) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27

Multnomah County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.3

Drainage

Well Drained

Dianthus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (137 days to spare)
Start indoors: Feb 11 Transplant: Feb 11 🌸 Bloom: Apr 1 – Jun 3
Recommended (50%) ✓ Fits season (140 days to spare)
Start indoors: Feb 17 Transplant: Feb 17 🌸 Bloom: Apr 7 – Jun 9
Safe Start (90%) ✓ Fits season (138 days to spare)
Start indoors: Mar 14 Transplant: Mar 14 🌸 Bloom: May 2 – Jul 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 Multnomah County

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

Soil pH

Your soil pH (5.8–6.3) overlaps with Dianthus's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Dianthus.

Organic Matter

Organic matter is excellent (4.5%) — Dianthus will thrive.

How to Plant Dianthus

0.1"
Planting Depth
8"
Between Plants
10"
Between Rows

Succession Planting Dianthus

3
successive plantings in your 196-day season

Sow every 6.9 weeks. Last sowing by Aug 08 to harvest before frost.

Dianthus Water Budget

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

Monthly Watering Guide for Dianthus

Dianthus 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 Dianthus Needs Rainfall You Supplement Action
Jan 5.8" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 2.2" 2.3" 0" ✅ Rainfall sufficient
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.3" 0.9" 💧 Light watering
Jul 2.2" 0.6" 1.6" 🚿 Regular watering
Aug 2.2" 0.7" 1.5" 🚿 Regular watering
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 2.2" 2.9" 0" ✅ Rainfall sufficient
Nov 6" 0" ❄️ Dormant
Dec 4.9" 0" ❄️ Dormant

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

Dianthus 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.

Dianthus needs ~910 GDD — county provides 2,548 GDD Excellent fit

Dianthus Planting Timeline — Multnomah County, OR

Dianthus Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors February 17 Feb 17 – Mar 3
Direct Sow February 17 Feb 17 – Mar 10
Bloom April 7 Apr 7 – Jun 9

Plant 0.1" deep · 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors Transplant Outdoors Direct Sow
March Start Indoors Transplant Outdoors Direct Sow
April Bloom
May Bloom
June Bloom
July
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

196 days in Multnomah County

Growing Tips for Dianthus in Multnomah County

Direct sow Dianthus outdoors after April 14 in Multnomah County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 8–10 weeks before last frost for spring transplants, or direct-sow in early spring as soon as soil can be worked — seeds tolerate light frost. Can also be direct-sown in late summer for fall bloom. Plant in full sun with excellent drainage; poorly drained soil causes crown rot. Deadhead regularly to extend bloom. In zones 8–10, plant as a fall annual for winter– spring color; plants decline in summer heat.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Dianthus in Multnomah County, OR?

Multnomah County is in Zone 9a with an average last frost of April 14. Plan your Dianthus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Multnomah County, OR?

Multnomah County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 14 and first fall frost is October 27.

🌱

Your Multnomah County Garden Planner — Free

A 22-page printable planner built for Multnomah County (Zone 9a). 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 Multnomah County, OR. Local conditions may vary. Last updated: June 2026.

Sources & credits

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