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When to Plant Dill in Jefferson County, WA

Jefferson County, Washington Zone 8b May

Jefferson County, Washington gardeners: here's your May plan

Each item below is timed to Jefferson County, Washington's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 14
Avg. first frost October 29
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.9 hrs
  1. Indoor seed-starting week for dill

    These need a head start before your last frost (April 14). Sow into cells now so you're ready to transplant in a few weeks.

  2. Start harvesting dill

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

June will be here before you know it — start on
  • First harvests: dill

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Dill is a feathery annual herb with aromatic leaves and seeds. Its fine foliage and umbrella-shaped flower heads attract beneficial insects to the garden.

Jefferson County, Washington is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 29, giving you a growing season of approximately 198 days.

At an elevation of 205 feet, Jefferson County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Dill during the growing season.

Jefferson County, WA (Zone 8b) Moderate season
198 days
Last Spring Frost April 14
198 growing days
First Fall Frost October 29
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Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (102 days to spare)
Start indoors: Mar 2 Transplant: Mar 30 🍅 Harvest: May 11 – Jul 13
Recommended (50%) ✓ Fits season (100 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🍅 Harvest: May 19 – Jul 21
Safe Start (90%) ✓ Fits season (96 days to spare)
Start indoors: Apr 4 Transplant: May 2 🍅 Harvest: Jun 13 – Aug 15

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 Jefferson County

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

Soil pH

Your soil pH (5.7–6.8) is within Dill's preferred range (5.5–7.0).

Soil Texture

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

Drainage

Drainage is adequate for Dill.

Organic Matter

Organic matter is excellent (5.7%) — Dill will thrive.

How to Plant Dill

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Dill

5
successive plantings in your 198-day season

Sow every 4.6 weeks. Last sowing by Aug 30 to harvest before frost.

For a dedicated fall crop, sow by Aug 20.

Plant Water Budget

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

Monthly Watering Guide for Dill

Dill 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 Dill Needs Rainfall You Supplement Action
Jan 6.4" 0" ❄️ Dormant
Feb 4.7" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 2.2" 2.6" 0" ✅ Rainfall sufficient
May 2.2" 2.1" 0.1" 💧 Light watering
Jun 2.2" 1.5" 0.7" 💧 Light watering
Jul 2.2" 0.5" 1.7" 🚿 Regular watering
Aug 2.2" 0.6" 1.6" 🚿 Regular watering
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 2.2" 3.5" 0" ✅ Rainfall sufficient
Nov 6.3" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

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

Dill 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.

Dill needs ~800 GDD — county provides 3,168 GDD Excellent fit

Dill Planting Timeline — Jefferson County, WA

Dill Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 7 Apr 7 – Apr 21
Direct Sow March 31 Mar 31 – Apr 21
Harvest May 19 May 19 – Jul 21
Fall Sowing August 20 Aug 20 – Sep 3

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August Fall Sowing
September Fall Sowing
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 8b

📆 Growing Season

198 days in Jefferson County

Growing Tips for Dill in Jefferson County

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

Your generous 198.0-day season in Jefferson County allows multiple plantings of Dill. Sow every 20.0 days for continuous harvest.

Common pests for Dill in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring as dill has a taproot and dislikes transplanting. Succession sow for continuous leaf harvest. Allow some plants to flower for seeds and to attract beneficial insects.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Dill in Jefferson County, WA?

Jefferson County is in Zone 8b with an average last frost of April 14. Plan your Dill planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, WA?

Jefferson County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 29.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Jefferson County, WA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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