When to plant Calendula in Riley County, KS
Riley County gardeners should plant Calendula between March 20 and April 10 in spring. With Riley County's Zone 6b climate (last frost April 17), Calendula needs 50–70 days to mature — plant by August 9 for a full harvest.
When to Plant Calendula in Riley County, KS
Your July game plan for Riley County, Kansas
Welcome to July in Zone 6b. These are the moves that will have the biggest impact on your growing season.
-
Pick calendula
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.
Riley County, Kansas is in USDA Zone 6b. The average last spring frost is April 17 and the first fall frost is October 18, giving you a growing season of approximately 184 days.
At an elevation of 551 feet, Riley County receives approximately 32.9 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Calendula during the growing season.
Riley County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.7
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 Riley County
How your county's soil matches Calendula's growing requirements.
Soil pH
Your soil pH (6.8–7.7) is more alkaline than Calendula prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Riley County is excellent for Calendula — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Calendula.
Organic Matter
Organic matter is moderate (3.4%). Annual compost additions will help Calendula.
How to Plant Calendula
Succession Planting Calendula
Sow every 5.7 weeks. Last sowing by Aug 09 to harvest before frost.
Calendula Water Budget
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 | — | 1" | 0" | ❄️ Dormant |
| Feb | — | 1.2" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Riley 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 — Riley County, KS
Calendula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 6 | Mar 6 – Mar 20 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Direct Sow | March 20 | Mar 20 – Apr 10 |
| Bloom | June 5 | Jun 5 – Sep 11 |
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 | Transplant Outdoors |
| 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: too_alkaline
🗺️ USDA Zone
Zone 6b
📆 Growing Season
184 days in Riley County
Growing Tips for Calendula in Riley County
Direct sow Calendula outdoors after April 17 in Riley 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 Riley County, KS?
Riley County is in Zone 6b with an average last frost of April 17. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Riley County, KS?
Riley County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 17 and first fall frost is October 18.
When should I plant Calendula in Riley County, KS?
In Riley County, KS, plant Calendula after the last frost (around April 17) and before the first frost (around October 18). Best results when soil holds above 50°F.
What growing zone is Riley County, KS for Calendula?
Riley 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 Riley County's climate?
Yes — Calendula grows well in Riley County's temperate climate. Riley County averages a 184-day frost-free season, with last frost around April 17 and first frost around October 18.
Your Riley County Garden Planner — Free
A 22-page printable planner built for Riley 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.