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When to Plant Chamomile in Big Horn County, MT

Chamomile is a daisy-like herb famous for its calming, apple-scented tea. German chamomile is an annual while Roman chamomile is a perennial ground cover.

Big Horn County, Montana is in USDA Zone 4b. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.

At an elevation of 5,955 feet, Big Horn County receives approximately 22.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Chamomile to ensure they mature before fall.

Big Horn County, MT (Zone 4b) Short season
140 days
Last Spring Frost May 13
140 growing days
First Fall Frost September 30

Big Horn County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 3 – Sep 11
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jul 8 – Sep 16
Safe Start (90%) ✓ Fits season (11 days to spare)
Start indoors: Apr 19 Transplant: May 24 🍅 Harvest: Jul 26 – Oct 4

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 Big Horn County

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

Soil pH

Your soil pH (6.2โ€“7.6) overlaps with Chamomile's range (5.6โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Big Horn County is excellent for Chamomile โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Chamomile.

How to Plant Chamomile

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Chamomile

2
successive plantings in your 140-day season

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

For a dedicated fall crop, sow by Jul 08.

Plant Water Budget

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

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Chamomile

Chamomile needs approximately 0.4 inches of water per week (1.7" per month). Here's how your county's rainfall compares month by month.

Month Chamomile Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.5" 0" โ„๏ธ Dormant
Mar โ€” 1.8" 0" โ„๏ธ Dormant
Apr โ€” 2.4" 0" โ„๏ธ Dormant
May 1.7" 2.9" 0" โœ… Rainfall sufficient
Jun 1.7" 1.7" 0" โœ… Rainfall sufficient
Jul 1.7" 2.2" 0" โœ… Rainfall sufficient
Aug 1.7" 2" 0" โœ… Rainfall sufficient
Sep 1.7" 1.8" 0" โœ… Rainfall sufficient
Oct โ€” 2.1" 0" โ„๏ธ Dormant
Nov โ€” 1.5" 0" โ„๏ธ Dormant
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Big Horn County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Chamomile 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" โ€” every day above 50ยฐF 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.

Chamomile needs ~919 GDD — county provides 1,715 GDD Excellent fit

Chamomile Planting Timeline โ€” Big Horn County, MT

Chamomile Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 โ€“ Apr 15
Transplant Outdoors May 6 May 6 โ€“ May 20
Direct Sow May 6 May 6 โ€“ May 27
Harvest July 8 Jul 8 โ€“ Sep 16
Fall Sowing July 8 Jul 8 โ€“ Jul 22

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.4"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 5.6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

140 days in Big Horn County

Growing Tips for Chamomile in Big Horn County

Direct sow Chamomile outdoors after May 13 in Big Horn County when soil has warmed and frost danger has passed.

Common pests for Chamomile in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow on the soil surface as seeds need light. Harvest flowers when petals begin to curl back. Chamomile self-sows freely and improves the health of nearby plants.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chamomile in Big Horn County, MT?

Big Horn County is in Zone 4b with an average last frost of May 13. Plan your Chamomile planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Big Horn County, MT?

Big Horn County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 13 and first fall frost is September 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Big Horn County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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