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When to plant Calendula in Morgan County County,

Morgan County County's short 148-day growing season means one Calendula planting between April 19 and May 10. No fall crop in Zone 5b.

When to Plant Calendula in Morgan County, CO

Morgan County, Colorado Zone 5b June

June in the garden — Morgan County, Colorado

Your Morgan County, Colorado garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 10
Avg. first frost October 5
Soil temp (4") 44°F
Watering Critical
Pest pressure High
Daylight 14.9 hrs
  1. Indoor seed-starting week for calendula

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Pick calendula

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Get ahead of July
  • 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.

Morgan County, Colorado is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 7,673 feet, Morgan County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Calendula to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Calendula successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Morgan County, CO (Zone 5b) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5

Morgan County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Mar 21 Transplant: May 2 🌸 Bloom: Jun 20 – Sep 19
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Mar 29 Transplant: May 10 🌸 Bloom: Jun 28 – Sep 27
Safe Start (90%) ✓ Fits season (9 days to spare)
Start indoors: Apr 8 Transplant: May 20 🌸 Bloom: Jul 8 – Oct 7

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 Morgan County

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

Soil pH

Your soil pH (6.7–8.2) is more alkaline than Calendula prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Calendula.

How to Plant Calendula

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

Succession Planting Calendula

3
successive plantings in your 148-day season

Sow every 5.7 weeks. Last sowing by Jul 27 to harvest before frost.

Calendula Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/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 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 1.3" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2.2" 2.2" 0" ✅ Rainfall sufficient
Jun 2.2" 1.1" 1.1" 🚿 Regular watering
Jul 2.2" 1.7" 0.5" 💧 Light watering
Aug 2.2" 1.7" 0.5" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 2.2" 1.7" 0.5" 💧 Light watering
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Morgan 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 ~780 GDD — county provides 1,924 GDD Excellent fit

Calendula Planting Timeline — Morgan County, CO

Calendula Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 19 Apr 19 – May 10
Bloom June 28 Jun 28 – Sep 27

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
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: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Morgan County

Growing Tips for Calendula in Morgan County

Direct sow Calendula outdoors after May 10 in Morgan 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.

Morgan County receives only 18" 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 Morgan County, CO?

Morgan County is in Zone 5b with an average last frost of May 10. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Morgan County, CO?

Morgan County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is October 5.

When should I plant Calendula in Morgan County, ?

In Morgan County, , plant Calendula after the last frost (around May 10) and before the first frost (around October 5). Best results when soil holds above 50°F.

What growing zone is Morgan County, for Calendula?

Morgan County sits in USDA Zone 5b. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.

Can Calendula grow in Morgan County's climate?

Yes — Calendula grows well in Morgan County's temperate climate. Morgan County averages a 148-day frost-free season, with last frost around May 10 and first frost around October 5.

🌱

Your Morgan County Garden Planner — Free

A 22-page printable planner built for Morgan County (Zone 5b). 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 Morgan County, CO. 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.