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When to Plant Catnip in Broadwater County, MT

Broadwater County, Montana Zone 5a May

Your May gardening checklist

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

Avg. last frost May 20
Avg. first frost September 20
Soil temp (4") 30°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
  1. Move catnip into the garden

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

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Catnip is a hardy perennial herb in the mint family known for its effect on cats. It also makes a calming tea and is a useful companion plant that repels some pests.

Broadwater County, Montana is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.

At an elevation of 7,806 feet, Broadwater County receives approximately 17.4 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Catnip to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Catnip successfully. Mulch heavily to conserve soil moisture.

Broadwater County, MT (Zone 5a) Short season
123 days
Last Spring Frost May 20
123 growing days
First Fall Frost September 20
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Broadwater County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 17 🍅 Harvest: Jul 19 – Sep 20
Recommended (50%) ✗ May not fit
Transplant: May 27 🍅 Harvest: Jul 29 – Sep 30
Safe Start (90%) ✗ May not fit
Transplant: Jun 23 🍅 Harvest: Aug 25 – Oct 27

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 Broadwater County

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

Soil pH

Your soil pH (6.6–8.1) overlaps with Catnip's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Catnip.

How to Plant Catnip

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

Succession Planting Catnip

2
successive plantings in your 123-day season

Sow every 6.9 weeks. Last sowing by Jul 02 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 Catnip

Catnip 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 Catnip Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2.2" 2" 0.2" 💧 Light watering
Jun 2.2" 1.2" 1" 💧 Light watering
Jul 2.2" 1.7" 0.5" 💧 Light watering
Aug 2.2" 1.6" 0.6" 💧 Light watering
Sep 2.2" 1.5" 0.7" 💧 Light watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Catnip 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.

Catnip needs ~858 GDD — county provides 1,506 GDD Excellent fit

Catnip Planting Timeline — Broadwater County, MT

Catnip Planting Calendar

Activity When Date Range
Transplant Outdoors May 27 May 27 – Jun 10
Harvest July 29 Jul 29 – Sep 30

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 Harvest
August Harvest
September Harvest
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

60–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

123 days in Broadwater County

Growing Tips for Catnip in Broadwater County

Direct sow Catnip outdoors after May 20 in Broadwater County when soil has warmed and frost danger has passed.

Broadwater County receives only 17" of rain annually. Catnip needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow or start indoors. Catnip is very easy to grow and can become invasive. Harvest leaves before flowering for tea. Protect young plants from cats.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Catnip in Broadwater County, MT?

Broadwater County is in Zone 5a with an average last frost of May 20. Plan your Catnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Broadwater County, MT?

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

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Your Broadwater County Garden Planner — Free

A 24-page printable planner built for Broadwater 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.

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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 Broadwater 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.