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When to Plant Calendula in Polk County, TX

Polk County, Texas Zone 9a July

Your July gardening checklist

July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Polk County, Texas.

Avg. last frost March 4
Avg. first frost November 23
Soil temp (4") 89°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Harvest calendula as they ripen

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

Get ahead of August
  • 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.

Polk County, Texas is in USDA Zone 9a. The average last spring frost is March 4 and the first fall frost is November 23, giving you a growing season of approximately 264 days.

At an elevation of 292 feet, Polk County receives approximately 63 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Calendula may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Calendula will need more frequent watering and organic matter to retain nutrients. 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
Polk County, TX (Zone 9a) Long season
264 days
Last Spring Frost March 4
264 growing days
First Fall Frost November 23

Polk County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Calendula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (127 days to spare)
Transplant: Jan 22 🌸 Bloom: Mar 5 – Jul 9
Recommended (50%) ✓ Fits season (124 days to spare)
Transplant: Feb 4 🌸 Bloom: Mar 18 – Jul 22
Safe Start (90%) ✓ Fits season (119 days to spare)
Transplant: Feb 28 🌸 Bloom: Apr 11 – Aug 15

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 Polk County

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

Soil pH

Your soil pH (5.2–6.6) overlaps with Calendula's range (5.5–7.0), though not a perfect match.

Soil Texture

Sandy soil in Polk County warms quickly in spring but drains fast. Calendula will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Calendula.

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Calendula

6
successive plantings in your 264-day season

Sow every 5.7 weeks. Last sowing by Sep 14 to harvest before frost.

For a dedicated fall crop, sow by Aug 31.

Calendula Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/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 1.4" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2.2" 4" 0" ✅ Rainfall sufficient
Apr 2.2" 5.8" 0" ✅ Rainfall sufficient
May 2.2" 8.5" 0" ✅ Rainfall sufficient
Jun 2.2" 11.4" 0" ✅ Rainfall sufficient
Jul 2.2" 7" 0" ✅ Rainfall sufficient
Aug 2.2" 7.9" 0" ✅ Rainfall sufficient
Sep 2.2" 6.5" 0" ✅ Rainfall sufficient
Oct 2.2" 4.4" 0" ✅ Rainfall sufficient
Nov 2.2" 2.1" 0.1" 💧 Light watering
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Polk 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 ~1,320 GDD — county provides 5,808 GDD Excellent fit

Calendula Planting Timeline — Polk County, TX

Calendula Planting Calendar

Activity When Date Range
Transplant Outdoors February 4 Feb 4 – Feb 18
Direct Sow January 7 Jan 7 – Jan 28
Bloom March 18 Mar 18 – Jul 22
Fall Sowing August 31 Aug 31 – Sep 14

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 9a

📆 Growing Season

264 days in Polk County

Growing Tips for Calendula in Polk County

Direct sow Calendula outdoors after March 04 in Polk County when soil has warmed and frost danger has passed.

Sandy soil in Polk County dries quickly — mulch Calendula with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 96°F in Polk County, provide afternoon shade for Calendula and water deeply in the morning.

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 Polk County, TX?

Polk County is in Zone 9a with an average last frost of March 4. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Polk County, TX?

Polk County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 4 and first fall frost is November 23.

🌱

Your Polk County Garden Planner — Free

A 22-page printable planner built for Polk County (Zone 9a). 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 Polk County, TX. 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.