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When to Plant Dill in Park County, MT

Park County, Montana Zone 5a May

What to do in May

Here's what deserves your attention in Park County, Montana this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost May 24
Avg. first frost September 20
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
  1. Transplant dill outside

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Direct-sow dill

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Coming up in June — start thinking about
  • Starting indoors: dill
  • 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.

Park County, Montana is in USDA Zone 5a. The average last spring frost is May 24 and the first fall frost is September 20, giving you a growing season of approximately 119 days.

At an elevation of 6,994 feet, Park County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Dill to ensure they mature before fall.

Park County, MT (Zone 5a) Short season
119 days
Last Spring Frost May 24
119 growing days
First Fall Frost September 20

Park County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Apr 9 Transplant: May 7 🍅 Harvest: Jun 18 – Aug 20
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: Apr 19 Transplant: May 17 🍅 Harvest: Jun 28 – Aug 30
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: May 13 Transplant: Jun 10 🍅 Harvest: Jul 22 – Sep 23

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 Park County

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

Soil pH

Your soil pH (6.5–7.6) is more alkaline than Dill prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Dill.

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

3
successive plantings in your 119-day season

Sow every 4.6 weeks. Last sowing by Jul 22 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

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

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 2.2" 2.5" 0" ✅ Rainfall sufficient
Jun 2.2" 1.7" 0.5" 💧 Light watering
Jul 2.2" 1.8" 0.4" 💧 Light watering
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Park 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 ~500 GDD — county provides 1,190 GDD Excellent fit

Dill Planting Timeline — Park County, MT

Dill Planting Calendar

Activity When Date Range
Start Indoors April 19 Apr 19 – May 3
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 10 May 10 – May 31
Harvest June 28 Jun 28 – Aug 30
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

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

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: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

119 days in Park County

Growing Tips for Dill in Park County

Direct sow Dill outdoors after May 24 in Park County when soil has warmed and frost danger has passed.

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 Park County, MT?

Park County is in Zone 5a with an average last frost of May 24. Plan your Dill planting based on this frost date — see the calendar above for exact timing.

What planting zone is Park County, MT?

Park County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 24 and first fall frost is September 20.

🌱

Your Park County Garden Planner — Free

A 24-page printable planner built for Park County (Zone 5a). 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 Park County, MT. 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.