When to Plant Dianthus in King County, WA
June in the garden — King County, Washington
If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.
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Indoor seed-starting week for dianthus
Label every cell. You will absolutely forget which is which otherwise.
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It's harvest week for dianthus
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
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.
King County, Washington is in USDA Zone 9a. The average last spring frost is April 7 and the first fall frost is October 30, giving you a growing season of approximately 206 days.
At an elevation of 258 feet, King County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Dianthus during the growing season.
King County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.4
Drainage
Well Drained
Dianthus 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 King County
How your county's soil matches Dianthus's growing requirements.
Soil pH
Your soil pH (5.7–6.4) overlaps with Dianthus's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in King County is excellent for Dianthus — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.5%) — Dianthus will thrive.
How to Plant Dianthus
Succession Planting Dianthus
Sow every 6.9 weeks. Last sowing by Aug 11 to harvest before frost.
Dianthus Water Budget
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 | — | 5.9" | 0" | ❄️ Dormant |
| Feb | — | 4.5" | 0" | ❄️ Dormant |
| Mar | — | 3.4" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 2" | 0.2" | 💧 Light watering |
| 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" | 3.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 5.6" | 0" | ❄️ Dormant |
| Dec | — | 5.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in King 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 Planting Timeline — King County, WA
Dianthus Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 10 | Feb 10 – Feb 24 |
| Transplant Outdoors | February 10 | Feb 10 – Feb 24 |
| Direct Sow | February 10 | Feb 10 – Mar 3 |
| Bloom | March 31 | Mar 31 – Jun 2 |
Plant 0.1" deep · 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Direct Sow Bloom |
| 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
206 days in King County
Growing Tips for Dianthus in King County
Direct sow Dianthus outdoors after April 07 in King 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 →
Dianthus in Other Locations
Frequently Asked Questions
When should I plant Dianthus in King County, WA?
King County is in Zone 9a with an average last frost of April 7. Plan your Dianthus planting based on this frost date — see the calendar above for exact timing.
What planting zone is King County, WA?
King County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is April 7 and first fall frost is October 30.
Your King County Garden Planner — Free
A 22-page printable planner built for King 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.