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When to plant Calendula in Logan County County,

Logan County County sits in cold Zone 5b. Plant Calendula April 20–May 11 for the single annual harvest; the October 5 first frost closes the window.

When to Plant Calendula in Logan County, CO

Logan County, Colorado Zone 5b June

Your June planting checklist for Logan County, Colorado

Your garden in Logan County, Colorado is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost May 11
Avg. first frost October 5
Soil temp (4") 52°F
Watering Critical
Pest pressure High
Daylight 14.9 hrs
  1. Get calendula seeds going inside

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Bring in the calendula

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

A few tasks this June that'll pay off in 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.

Logan County, Colorado is in USDA Zone 5b. The average last spring frost is May 11 and the first fall frost is October 5, giving you a growing season of approximately 147 days.

At an elevation of 6,511 feet, Logan County receives approximately 14.9 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. 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
Logan County, CO (Zone 5b) Short season
147 days
Last Spring Frost May 11
147 growing days
First Fall Frost October 5
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Logan County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.9

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 (7 days to spare)
Start indoors: Mar 30 Transplant: May 11 🌸 Bloom: Jun 29 – Sep 28
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Apr 9 Transplant: May 21 🌸 Bloom: Jul 9 – Oct 8

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 Logan County

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

Soil pH

Your soil pH (6.4–7.9) is more alkaline than Calendula prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). 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 147-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
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 117 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" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 2.2" 1.7" 0.5" 💧 Light watering
Jun 2.2" 1.2" 1" 💧 Light watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 2.2" 1.3" 0.9" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Logan 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 1,800 GDD Excellent fit

Calendula Planting Timeline — Logan County, CO

Calendula Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 11 May 11 – May 25
Direct Sow April 20 Apr 20 – May 11
Bloom June 29 Jun 29 – Sep 28

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

147 days in Logan County

Growing Tips for Calendula in Logan County

Direct sow Calendula outdoors after May 11 in Logan 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.

Logan County receives only 15" 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 Logan County, CO?

Logan County is in Zone 5b with an average last frost of May 11. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Logan County, CO?

Logan County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 11 and first fall frost is October 5.

When should I plant Calendula in Logan County, ?

In Logan County, , plant Calendula after the last frost (around May 11) and before the first frost (around October 5). Best results when soil holds above 50°F.

What growing zone is Logan County, for Calendula?

Logan 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 Logan County's climate?

Yes — Calendula grows well in Logan County's temperate climate. Logan County averages a 147-day frost-free season, with last frost around May 11 and first frost around October 5.

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Your Logan County Garden Planner — Free

A 22-page printable planner built for Logan 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 Logan 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.