Blog

When to plant Calendula in Cook County County,

Cook County County's short 132-day growing season means one Calendula planting between May 13 and June 3. No fall crop in Zone 3b.

When to Plant Calendula in Cook County, MN

Cook County, Minnesota Zone 3b June

Top priorities for Cook County, Minnesota gardeners in June

June is a pivotal month for Cook County, Minnesota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 20
Avg. first frost September 29
Soil temp (4") 63°F
Watering Low
Pest pressure Moderate
Daylight 15.8 hrs
July will be here before you know it — start on
  • Starting indoors: calendula
  • First harvests: calendula

Instant PDF download. No spam, unsubscribe any time.

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.

Cook County, Minnesota is in USDA Zone 3b. The average last spring frost is May 20 and the first fall frost is September 29, giving you a growing season of approximately 132 days.

At an elevation of 1,068 feet, Cook County receives approximately 34.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Calendula to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Cook County, MN (Zone 3b) Short season
132 days
Last Spring Frost May 20
132 growing days
First Fall Frost September 29
Share this guide:

Cook County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Mar 27 Transplant: May 15 🌸 Bloom: Jul 3 – Sep 11
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Apr 1 Transplant: May 20 🌸 Bloom: Jul 8 – Sep 16
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Apr 12 Transplant: May 31 🌸 Bloom: Jul 19 – Sep 27

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 Cook County

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

Soil pH

Your soil pH (6.1–7.1) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Calendula will thrive.

How to Plant Calendula

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

Succession Planting Calendula

3
successive plantings in your 132-day season

Sow every 5.7 weeks. Last sowing by Jul 21 to harvest before frost.

Calendula Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/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 1.4" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 2.2" 3.4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.7" 0" ✅ Rainfall sufficient
Jul 2.2" 3.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.7" 0" ❄️ Dormant
Nov 2.5" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Cook 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 ~600 GDD — county provides 1,320 GDD Excellent fit

Calendula Planting Timeline — Cook County, MN

Calendula Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 13 May 13 – Jun 3
Bloom July 8 Jul 8 – Sep 16

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Bloom
August Bloom
September Bloom
October
November
December
Share this guide:

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 3b

📆 Growing Season

132 days in Cook County

Growing Tips for Calendula in Cook County

Direct sow Calendula outdoors after May 20 in Cook 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 Cook County, MN?

Cook County is in Zone 3b with an average last frost of May 20. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cook County, MN?

Cook County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 20 and first fall frost is September 29.

When should I plant Calendula in Cook County County, ?

In Cook County County, , plant Calendula after the last frost (around May 20) and before the first frost (around September 29). Best results when soil holds above 50°F.

What growing zone is Cook County County, for Calendula?

Cook County County sits in USDA Zone 3b. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.

Can Calendula grow in Cook County County's climate?

Yes — Calendula grows well in Cook County County's temperate climate. Cook County County averages a 132-day frost-free season, with last frost around May 20 and first frost around September 29.

🌱

Your Cook County Garden Planner — Free

A 22-page printable planner built for Cook County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Cook County, MN. 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.