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When to plant Calendula in Kootenai County County,

Kootenai County County sits in USDA Zone 6b. Plant Calendula between April 1 (after last frost on April 29) and April 22.

When to Plant Calendula in Kootenai County, ID

Kootenai County, Idaho Zone 6b June

This month in Kootenai County, Idaho

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

Avg. last frost April 29
Avg. first frost October 8
Soil temp (4") 53°F
Watering High
Pest pressure High
Daylight 15.8 hrs
  1. Sow calendula in trays indoors

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Start harvesting calendula

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Looking ahead to 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.

Kootenai County, Idaho is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 8, giving you a growing season of approximately 162 days.

At an elevation of 5,986 feet, Kootenai County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Calendula during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Kootenai County, ID (Zone 6b) Moderate season
162 days
Last Spring Frost April 29
162 growing days
First Fall Frost October 8

Kootenai County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Mar 11 Transplant: Apr 22 🌸 Bloom: Jun 10 – Sep 16
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 18 Transplant: Apr 29 🌸 Bloom: Jun 17 – Sep 23
Safe Start (90%) ✓ Fits season (18 days to spare)
Start indoors: Apr 5 Transplant: May 17 🌸 Bloom: Jul 5 – Oct 11

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 Kootenai County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Calendula prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). 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 162-day season

Sow every 5.7 weeks. Last sowing by Jul 30 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 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 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.2" 2.4" 0" ✅ Rainfall sufficient
May 2.2" 2.7" 0" ✅ Rainfall sufficient
Jun 2.2" 1.3" 0.9" 💧 Light watering
Jul 2.2" 1.9" 0.3" 💧 Light watering
Aug 2.2" 2" 0.2" 💧 Light watering
Sep 2.2" 1.9" 0.3" 💧 Light watering
Oct 2.2" 1.5" 0.7" 💧 Light watering
Nov 1.3" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Kootenai 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 ~870 GDD — county provides 2,349 GDD Excellent fit

Calendula Planting Timeline — Kootenai County, ID

Calendula Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 1 Apr 1 – Apr 22
Bloom June 17 Jun 17 – Sep 23

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors
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 6b

📆 Growing Season

162 days in Kootenai County

Growing Tips for Calendula in Kootenai County

Direct sow Calendula outdoors after April 29 in Kootenai 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.

Kootenai County receives only 21" 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 Kootenai County, ID?

Kootenai County is in Zone 6b with an average last frost of April 29. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kootenai County, ID?

Kootenai County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is April 29 and first fall frost is October 8.

When should I plant Calendula in Kootenai County County, ?

In Kootenai County County, , plant Calendula after the last frost (around April 29) and before the first frost (around October 8). Best results when soil holds above 50°F.

What growing zone is Kootenai County County, for Calendula?

Kootenai County 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 Kootenai County County's climate?

Yes — Calendula grows well in Kootenai County County's temperate climate. Kootenai County County averages a 162-day frost-free season, with last frost around April 29 and first frost around October 8.

🌱

Your Kootenai County Garden Planner — Free

A 22-page printable planner built for Kootenai 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 Kootenai 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.