When to plant Calendula in Phillips County, MT
In Phillips County, Calendula is a spring-only crop. Plant May 11–June 1 once soil hits 50°F.
When to Plant Calendula in Phillips County, MT
Phillips County, Montana gardeners: here's your June plan
We've pulled the most time-sensitive tasks for Phillips County, Montana this June and put them front and centre. Tackle them in order.
Looking ahead to July
- Starting indoors: calendula
- 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.
Phillips County, Montana is in USDA Zone 3b. The average last spring frost is May 18 and the first fall frost is September 21, giving you a growing season of approximately 126 days.
At an elevation of 6,886 feet, Phillips County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Calendula to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Calendula successfully. Mulch heavily to conserve soil moisture.
Phillips County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.6
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 Phillips County
How your county's soil matches Calendula's growing requirements.
Soil pH
Your soil pH (6.7–7.6) is more alkaline than Calendula prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Phillips County is excellent for Calendula — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Calendula.
How to Plant Calendula
Succession Planting Calendula
Sow every 5.7 weeks. Last sowing by Jul 13 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 1.9" | 0" | ❄️ Dormant |
| May | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Jul | 2.2" | 1.6" | 0.6" | 💧 Light watering |
| Aug | 2.2" | 2" | 0.2" | 💧 Light watering |
| Sep | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 1.3" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Phillips 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 — Phillips County, MT
Calendula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 30 | Mar 30 – Apr 13 |
| Transplant Outdoors | May 18 | May 18 – Jun 1 |
| Direct Sow | May 11 | May 11 – Jun 1 |
| Bloom | July 6 | Jul 6 – Sep 14 |
Plant 0.3" deep · 9" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| 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 3b
📆 Growing Season
126 days in Phillips County
Growing Tips for Calendula in Phillips County
Direct sow Calendula outdoors after May 18 in Phillips 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.
Phillips County receives only 19" of rain annually. Calendula needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Phillips County, MT?
Phillips County is in Zone 3b with an average last frost of May 18. Plan your Calendula planting based on this frost date — see the calendar above for exact timing.
What planting zone is Phillips County, MT?
Phillips County, Montana is in USDA Hardiness Zone 3b. The average last spring frost is May 18 and first fall frost is September 21.
When should I plant Calendula in Phillips County, MT?
In Phillips County, MT, plant Calendula after the last frost (around May 18) and before the first frost (around September 21). Best results when soil holds above 50°F.
What growing zone is Phillips County, MT for Calendula?
Phillips County sits in USDA Zone 3b. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.
Can Calendula grow in Phillips County's climate?
Yes — Calendula grows well in Phillips County's temperate climate. Phillips County averages a 126-day frost-free season, with last frost around May 18 and first frost around September 21.
Your Phillips County Garden Planner — Free
A 22-page printable planner built for Phillips County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.