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When to plant Calendula in Power County County,

In Power County County, Calendula is a single-season spring crop — there's no second fall window. Plant April 13–May 4 for an 70-day harvest, finishing well before the September 30 first frost.

When to Plant Calendula in Power County, ID

Power County, Idaho Zone 6a June

Top priorities for Power County, Idaho gardeners in June

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Power County, Idaho.

Avg. last frost May 11
Avg. first frost September 30
Soil temp (4") 49°F
Watering Critical
Pest pressure High
Daylight 15.1 hrs
  1. Begin indoor sowing: calendula

    Label every cell. You will absolutely forget which is which otherwise.

  2. It's harvest week for calendula

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

Coming up in July — start thinking about
  • 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.

Power County, Idaho is in USDA Zone 6a. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 6,609 feet, Power County receives approximately 14 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Calendula during the growing season. 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
Power County, ID (Zone 6a) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30

Power County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Mar 21 Transplant: May 2 🌸 Bloom: Jun 20 – Sep 19
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Mar 30 Transplant: May 11 🌸 Bloom: Jun 29 – Sep 28
Safe Start (90%) ✗ May not fit
Start indoors: Apr 30 Transplant: Jun 11 🌸 Bloom: Jul 30 – Oct 29

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 Power County

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

Soil pH

Your soil pH (6.6–8.2) is more alkaline than Calendula prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 142-day season

Sow every 5.7 weeks. Last sowing by Jul 22 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 130 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" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 2.2" 1.7" 0.5" 💧 Light watering
Jun 2.2" 0.9" 1.3" 🚿 Regular watering
Jul 2.2" 1.4" 0.8" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.2" 1" 💧 Light watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Power 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 ~915 GDD — county provides 2,165 GDD Excellent fit

Calendula Planting Timeline — Power County, ID

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 13 Apr 13 – May 4
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

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 6a

📆 Growing Season

142 days in Power County

Growing Tips for Calendula in Power County

Direct sow Calendula outdoors after May 11 in Power 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.

Power County receives only 14" 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 Power County, ID?

Power County is in Zone 6a 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 Power County, ID?

Power County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 11 and first fall frost is September 30.

When should I plant Calendula in Power County County, ?

In Power County County, , plant Calendula after the last frost (around May 11) and before the first frost (around September 30). Best results when soil holds above 50°F.

What growing zone is Power County County, for Calendula?

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

Can Calendula grow in Power County County's climate?

Yes — Calendula grows well in Power County County's temperate climate. Power County County averages a 142-day frost-free season, with last frost around May 11 and first frost around September 30.

🌱

Your Power County Garden Planner — Free

A 22-page printable planner built for Power County (Zone 6a). 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 Power County, ID. 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.