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When to plant Calendula in Cole County, MO

Aim to plant Calendula in Cole County on or after March 10; the window stays open through March 31. Cole County's 204-day frost-free season gives you enough for a full main crop and a short fall succession.

When to Plant Calendula in Cole County, MO

Cole County, Missouri Zone 6b August

August to-do list for Cole County, Missouri

We've pulled the most time-sensitive tasks for Cole County, Missouri this August and put them front and centre. Tackle them in order.

Avg. last frost April 7
Avg. first frost October 28
Soil temp (4") 82°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Pick calendula

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

A few tasks this August that'll pay off in September
  • 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.

Cole County, Missouri is in USDA Zone 6b. The average last spring frost is April 7 and the first fall frost is October 28, giving you a growing season of approximately 204 days.

At an elevation of 614 feet, Cole County receives approximately 39.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Calendula during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Cole County, MO (Zone 6b) Long season
204 days
Last Spring Frost April 7
204 growing days
First Fall Frost October 28

Cole County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.9

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Feb 17 Transplant: Mar 31 🌸 Bloom: May 19 – Aug 25
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Feb 24 Transplant: Apr 7 🌸 Bloom: May 26 – Sep 1
Safe Start (90%) ✓ Fits season (58 days to spare)
Start indoors: Mar 11 Transplant: Apr 22 🌸 Bloom: Jun 10 – Sep 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 Cole County

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

Soil pH

Your soil pH (5.4–6.9) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Calendula prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Calendula.

How to Plant Calendula

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

Succession Planting Calendula

4
successive plantings in your 204-day season

Sow every 5.7 weeks. Last sowing by Aug 19 to harvest before frost.

Calendula Water Budget

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

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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.2" 4.4" 0" ✅ Rainfall sufficient
May 2.2" 4.6" 0" ✅ Rainfall sufficient
Jun 2.2" 5.5" 0" ✅ Rainfall sufficient
Jul 2.2" 4.2" 0" ✅ Rainfall sufficient
Aug 2.2" 4.1" 0" ✅ Rainfall sufficient
Sep 2.2" 3.6" 0" ✅ Rainfall sufficient
Oct 2.2" 2.8" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cole 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 ~960 GDD — county provides 3,264 GDD Excellent fit

Calendula Planting Timeline — Cole County, MO

Calendula Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 7 Apr 7 – Apr 21
Direct Sow March 10 Mar 10 – Mar 31
Bloom May 26 May 26 – Sep 1

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Direct Sow
April Transplant Outdoors
May Bloom
June Bloom
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: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

204 days in Cole County

Growing Tips for Calendula in Cole County

Direct sow Calendula outdoors after April 07 in Cole 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.

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 Cole County, MO?

Cole County is in Zone 6b with an average last frost of April 7. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cole County, MO?

Cole County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 7 and first fall frost is October 28.

When should I plant Calendula in Cole County, MO?

In Cole County, MO, plant Calendula after the last frost (around April 7) and before the first frost (around October 28). Best results when soil holds above 50°F.

What growing zone is Cole County, MO for Calendula?

Cole County sits in USDA Zone 6b. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.

Can Calendula grow in Cole County's climate?

Yes — Calendula grows well in Cole County's temperate climate. Cole County averages a 204-day frost-free season, with last frost around April 7 and first frost around October 28.

🌱

Your Cole County Garden Planner — Free

A 22-page printable planner built for Cole County (Zone 6b). 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 Cole County, MO. Local conditions may vary. Last updated: August 2026.

Sources & credits

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