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When to plant Calendula in Cascade County County,

Cascade County County's short 125-day growing season means one Calendula planting between May 5 and May 26. No fall crop in Zone 4b.

When to Plant Calendula in Cascade County, MT

Cascade County, Montana Zone 4b June

June to-do list for Cascade County, Montana

Welcome to June in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 19
Avg. first frost September 21
Soil temp (4") 44°F
Watering High
Pest pressure High
Daylight 15.7 hrs
Coming up in July — start thinking about
  • Starting indoors: calendula
  • First harvests: calendula

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Calendula (Calendula officinalis) is a cheerful, edible-flowered cool-season annual valued by herbalists, chefs, and gardeners alike. Its golden-orange petals are used in salves, teas, and as a saffron substitute. Hardy enough to tolerate light frosts, it blooms prolifically in spring and fall, taking a pause during the hottest weeks of summer.

Cascade County, Montana is in USDA Zone 4b. The average last spring frost is May 19 and the first fall frost is September 21, giving you a growing season of approximately 125 days.

At an elevation of 6,585 feet, Cascade County receives approximately 21.8 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Calendula to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Cascade County, MT (Zone 4b) Short season
125 days
Last Spring Frost May 19
125 growing days
First Fall Frost September 21

Cascade County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 24 Transplant: May 12 🌸 Bloom: Jun 30 – Sep 15
Recommended (50%) ✗ May not fit
Start indoors: Mar 31 Transplant: May 19 🌸 Bloom: Jul 7 – Sep 22
Safe Start (90%) ✗ May not fit
Start indoors: Apr 24 Transplant: Jun 12 🌸 Bloom: Jul 31 – Oct 16

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 Cascade County

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

Soil pH

Your soil pH (6.8–8.2) is more alkaline than Calendula prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Calendula.

Organic Matter

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

How to Plant Calendula

0.3"
Planting Depth
9"
Between Plants
12"
Between Rows

Succession Planting Calendula

2
successive plantings in your 125-day season

Sow every 5.7 weeks. Last sowing by Jul 13 to harvest before frost.

Calendula Water Budget

Plant needs
0.5″/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 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Calendula

Calendula 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 Calendula Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.5" 0.7" 💧 Light watering
Jul 2.2" 2.1" 0.1" 💧 Light watering
Aug 2.2" 2" 0.2" 💧 Light watering
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Calendula 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.

Calendula needs ~735 GDD — county provides 1,531 GDD Excellent fit

Calendula Planting Timeline — Cascade County, MT

Calendula Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 – Apr 14
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 5 May 5 – May 26
Bloom July 7 Jul 7 – Sep 22

Plant 0.3" deep · 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

125 days in Cascade County

Growing Tips for Calendula in Cascade County

Direct sow Calendula outdoors after May 19 in Cascade County when soil has warmed and frost danger has passed.

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

Cascade County receives only 22" of rain annually. Calendula needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow in early spring as soon as soil can be worked — seeds germinate in cool soil (50-65°F). In zones 7+, also sow in fall for winter/spring bloom. Deadhead consistently to extend bloom. Plants self-seed readily; save a few spent heads and allow them to drop. Harvest petals when flowers are fully open for best flavor and medicinal value.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Calendula in Cascade County, MT?

Cascade County is in Zone 4b with an average last frost of May 19. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cascade County, MT?

Cascade County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 19 and first fall frost is September 21.

When should I plant Calendula in Cascade County, ?

In Cascade County, , plant Calendula after the last frost (around May 19) and before the first frost (around September 21). Best results when soil holds above 50°F.

What growing zone is Cascade County, for Calendula?

Cascade County sits in USDA Zone 4b. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.

Can Calendula grow in Cascade County's climate?

Yes — Calendula grows well in Cascade County's temperate climate. Cascade County averages a 125-day frost-free season, with last frost around May 19 and first frost around September 21.

🌱

Your Cascade County Garden Planner — Free

A 22-page printable planner built for Cascade 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 Cascade County, MT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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