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When to Plant Lovage in Petroleum County, MT

Petroleum County, Montana Zone 4b May

Top priorities for Petroleum County, Montana gardeners in May

May is a pivotal month for Petroleum County, Montana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 18
Avg. first frost September 24
Soil temp (4") 30°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Transplant lovage outside

    Frost risk is low now in Petroleum County, Montana. If you've been covering beds overnight, you can stop.

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Lovage is a large perennial herb with a celery-like flavor that can grow 4-6 feet tall. All parts are edible including the leaves, stems, seeds, and roots.

Petroleum County, Montana is in USDA Zone 4b. The average last spring frost is May 18 and the first fall frost is September 24, giving you a growing season of approximately 129 days.

At an elevation of 8,358 feet, Petroleum County receives approximately 13.7 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Lovage to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Lovage successfully. Mulch heavily to conserve soil moisture.

Petroleum County, MT (Zone 4b) Short season
129 days
Last Spring Frost May 18
129 growing days
First Fall Frost September 24
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Petroleum County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 18 🍅 Harvest: Jul 27 – Sep 28
Recommended (50%) ✗ May not fit
Transplant: May 25 🍅 Harvest: Aug 3 – Oct 5
Safe Start (90%) ✗ May not fit
Transplant: Jun 6 🍅 Harvest: Aug 15 – Oct 17

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 Petroleum County

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

Soil pH

Your soil pH (6.8–8.2) is more alkaline than Lovage prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Lovage.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Lovage.

How to Plant Lovage

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

Succession Planting Lovage

2
successive plantings in your 129-day season

Sow every 8 weeks. Last sowing by Jun 26 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,177 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lovage

Lovage needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Lovage Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 4.3" 1.8" 2.5" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1.2" 3.1" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Lovage 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.

Lovage needs ~860 GDD — county provides 1,386 GDD Excellent fit

Lovage Planting Timeline — Petroleum County, MT

Lovage Planting Calendar

Activity When Date Range
Transplant Outdoors May 25 May 25 – Jun 8
Harvest August 3 Aug 3 – Oct 5

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August Harvest
September Harvest
October Harvest
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

129 days in Petroleum County

Growing Tips for Lovage in Petroleum County

Direct sow Lovage outdoors after May 18 in Petroleum County when soil has warmed and frost danger has passed.

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

Petroleum County receives only 14" of rain annually. Lovage needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors or direct sow in spring. One plant is usually enough for a family. Harvest outer stems and leaves as needed. Divide clumps every 3-4 years.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lovage in Petroleum County, MT?

Petroleum County is in Zone 4b with an average last frost of May 18. Plan your Lovage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Petroleum County, MT?

Petroleum County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 18 and first fall frost is September 24.

🌱

Your Petroleum County Garden Planner — Free

A 24-page printable planner built for Petroleum County (Zone 4b). 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 Petroleum 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.