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When to Plant Calendula in Rhea County, TN

Rhea County, Tennessee Zone 7b July

July in Rhea County, Tennessee — your action list

We've pulled the most time-sensitive tasks for Rhea County, Tennessee this July and put them front and centre. Tackle them in order.

Avg. last frost April 13
Avg. first frost October 22
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. Basket week: 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 July that'll pay off in August
  • First harvests: calendula
  • Fall sowing: 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.

Rhea County, Tennessee is in USDA Zone 7b. The average last spring frost is April 13 and the first fall frost is October 22, giving you a growing season of approximately 192 days.

At an elevation of 3,363 feet, Rhea County receives approximately 50.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Calendula during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Calendula root diseases.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Rhea County, TN (Zone 7b) Moderate season
192 days
Last Spring Frost April 13
192 growing days
First Fall Frost October 22

Rhea County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (25 days to spare)
Start indoors: Feb 24 Transplant: Apr 7 🌸 Bloom: May 26 – Sep 22
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Mar 2 Transplant: Apr 13 🌸 Bloom: Jun 1 – Sep 28
Safe Start (90%) ✓ Fits season (18 days to spare)
Start indoors: Mar 20 Transplant: May 1 🌸 Bloom: Jun 19 – Oct 16

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 Rhea County

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

Soil pH

Your soil pH (5.5–7.0) is within Calendula's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Calendula.

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 192-day season

Sow every 5.7 weeks. Last sowing by Aug 13 to harvest before frost.

For a dedicated fall crop, sow by Aug 27.

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

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 4.2" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 3.9" 0" ✅ Rainfall sufficient
Jul 2.2" 5.4" 0" ✅ Rainfall sufficient
Aug 2.2" 5.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.7" 0" ✅ Rainfall sufficient
Oct 2.2" 3.6" 0" ✅ Rainfall sufficient
Nov 3.8" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Rhea 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 ~1,140 GDD — county provides 3,648 GDD Excellent fit

Calendula Planting Timeline — Rhea County, TN

Calendula Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow March 9 Mar 9 – Mar 30
Bloom June 1 Jun 1 – Sep 28
Fall Sowing August 27 Aug 27 – Sep 10

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7b

📆 Growing Season

192 days in Rhea County

Growing Tips for Calendula in Rhea County

Direct sow Calendula outdoors after April 13 in Rhea 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 Rhea County, TN?

Rhea County is in Zone 7b with an average last frost of April 13. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rhea County, TN?

Rhea County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 13 and first fall frost is October 22.

🌱

Your Rhea County Garden Planner — Free

A 22-page printable planner built for Rhea County (Zone 7b). 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 Rhea County, TN. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.