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When to plant Calendula in Harper County County,

Harper County County sits in USDA Zone 7a. Plant Calendula between March 5 (after last frost on April 9) and March 26. A second sowing from September 1 to September 15 extends the harvest into fall.

When to Plant Calendula in Harper County, KS

Harper County, Kansas Zone 7a June

Your June gardening checklist

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

Avg. last frost April 9
Avg. first frost October 27
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.5 hrs
  1. Start harvesting calendula

    If you can't use it all right away, check the food-preservation section of your planner.

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.

Harper County, Kansas is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 27, giving you a growing season of approximately 201 days.

At an elevation of 745 feet, Harper County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Calendula during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Harper County, KS (Zone 7a) Long season
201 days
Last Spring Frost April 9
201 growing days
First Fall Frost October 27
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Harper County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Feb 20 Transplant: Apr 3 🌸 Bloom: May 22 – Sep 4
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Feb 26 Transplant: Apr 9 🌸 Bloom: May 28 – Sep 10
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Mar 11 Transplant: Apr 22 🌸 Bloom: Jun 10 – Sep 23

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 Harper County

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

Soil pH

Your soil pH (6.2–7.8) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Calendula.

Organic Matter

Organic matter is excellent (4.1%) — Calendula will thrive.

How to Plant Calendula

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

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Calendula

4
successive plantings in your 201-day season

Sow every 5.7 weeks. Last sowing by Aug 18 to harvest before frost.

For a dedicated fall crop, sow by Sep 01.

Calendula Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 153 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 0.7" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 2.6" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 3.6" 0" ✅ Rainfall sufficient
Aug 2.2" 3.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2.7" 0" ✅ Rainfall sufficient
Oct 2.2" 1.9" 0.3" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Harper 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 ~960 GDD — county provides 3,216 GDD Excellent fit

Calendula Planting Timeline — Harper County, KS

Calendula Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow March 5 Mar 5 – Mar 26
Bloom May 28 May 28 – Sep 10
Fall Sowing September 1 Sep 1 – Sep 15

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Direct Sow
April Transplant Outdoors
May Bloom
June Bloom
July Bloom
August Bloom
September Fall Sowing 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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

201 days in Harper County

Growing Tips for Calendula in Harper County

Direct sow Calendula outdoors after April 09 in Harper 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 Harper County, KS?

Harper County is in Zone 7a with an average last frost of April 9. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harper County, KS?

Harper County, Kansas is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 27.

When should I plant Calendula in Harper County, ?

In Harper County, , plant Calendula after the last frost (around April 9) and before the first frost (around October 27). Best results when soil holds above 50°F.

What growing zone is Harper County, for Calendula?

Harper County sits in USDA Zone 7a. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.

Can Calendula grow in Harper County's climate?

Yes — Calendula grows well in Harper County's temperate climate. Harper County averages a 201-day frost-free season, with last frost around April 9 and first frost around October 27.

🌱

Your Harper County Garden Planner — Free

A 22-page printable planner built for Harper County (Zone 7a). 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 Harper County, KS. 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.