When to plant Calendula in Warren County, MO
Spring Calendula in Warren County goes in March 14–April 4, once nighttime temps stop dipping near freezing.
When to Plant Calendula in Warren County, MO
Your August game plan for Warren County, Missouri
If you only do a handful of things in the garden this August, make it these. They're sequenced around your zone's frost timing.
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Start harvesting calendula
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
To set up a strong September, finish these tasks
- First harvests: calendula
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.
Warren County, Missouri is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 25, giving you a growing season of approximately 197 days.
At an elevation of 654 feet, Warren County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Calendula during the growing season.
Warren County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.5
Drainage
Well Drained
Calendula Planting Risk Windows
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 Warren County
How your county's soil matches Calendula's growing requirements.
Soil pH
Your soil pH (5.5–6.5) is within Calendula's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Warren County is excellent for Calendula — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.1%). Annual compost additions will help Calendula.
How to Plant Calendula
Succession Planting Calendula
Sow every 5.7 weeks. Last sowing by Aug 16 to harvest before frost.
Calendula Water Budget
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Warren 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 Planting Timeline — Warren County, MO
Calendula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 28 | Feb 28 – Mar 14 |
| Transplant Outdoors | April 11 | Apr 11 – Apr 25 |
| Direct Sow | March 14 | Mar 14 – Apr 4 |
| Bloom | May 30 | May 30 – Sep 5 |
Plant 0.3" deep · 9" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Bloom |
| 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: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
197 days in Warren County
Growing Tips for Calendula in Warren County
Direct sow Calendula outdoors after April 11 in Warren 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 →
Calendula in Other Locations
Frequently Asked Questions
When should I plant Calendula in Warren County, MO?
Warren County is in Zone 6b with an average last frost of April 11. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Warren County, MO?
Warren County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 25.
When should I plant Calendula in Warren County, MO?
In Warren County, MO, plant Calendula after the last frost (around April 11) and before the first frost (around October 25). Best results when soil holds above 50°F.
What growing zone is Warren County, MO for Calendula?
Warren 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 Warren County's climate?
Yes — Calendula grows well in Warren County's temperate climate. Warren County averages a 197-day frost-free season, with last frost around April 11 and first frost around October 25.
Your Warren County Garden Planner — Free
A 22-page printable planner built for Warren 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.