When to plant Calendula in Lee County, IA
Lee County sits in USDA Zone 6a. Plant Calendula between March 19 (after last frost on April 16) and April 9.
When to Plant Calendula in Lee County, IA
Top priorities for Lee County, Iowa gardeners in July
Your Lee County, Iowa garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.
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Harvest calendula as they ripen
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
August will be here before you know it — start on
- 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.
Lee County, Iowa is in USDA Zone 6a. The average last spring frost is April 16 and the first fall frost is October 18, giving you a growing season of approximately 185 days.
At an elevation of 1,393 feet, Lee County receives approximately 36.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Calendula to ensure they mature before fall.
Lee County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-7.2
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 Lee County
How your county's soil matches Calendula's growing requirements.
Soil pH
Your soil pH (6.1–7.2) overlaps with Calendula's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Lee 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 (4.4%) — Calendula will thrive.
How to Plant Calendula
Succession Planting Calendula
Sow every 5.7 weeks. Last sowing by Aug 09 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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Lee 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 — Lee County, IA
Calendula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 5 | Mar 5 – Mar 19 |
| Transplant Outdoors | April 16 | Apr 16 – Apr 30 |
| Direct Sow | March 19 | Mar 19 – Apr 9 |
| Bloom | June 4 | Jun 4 – Sep 3 |
Plant 0.3" deep · 9" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| 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: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
185 days in Lee County
Growing Tips for Calendula in Lee County
Direct sow Calendula outdoors after April 16 in Lee 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 Lee County, IA?
Lee County is in Zone 6a with an average last frost of April 16. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lee County, IA?
Lee County, Iowa is in USDA Hardiness Zone 6a. The average last spring frost is April 16 and first fall frost is October 18.
When should I plant Calendula in Lee County, IA?
In Lee County, IA, plant Calendula after the last frost (around April 16) and before the first frost (around October 18). Best results when soil holds above 50°F.
What growing zone is Lee County, IA for Calendula?
Lee County sits in USDA Zone 6a. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.
Can Calendula grow in Lee County's climate?
Yes — Calendula grows well in Lee County's temperate climate. Lee County averages a 185-day frost-free season, with last frost around April 16 and first frost around October 18.
Your Lee County Garden Planner — Free
A 22-page printable planner built for Lee County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.