When to Plant Celeriac in Roosevelt County, MT
Celeriac is a celery relative grown for its knobby, flavorful root rather than its stalks. It has a rich celery flavor and is excellent roasted, mashed, or in soups.
Roosevelt County, Montana is in USDA Zone 3b. The average last spring frost is May 17 and the first fall frost is September 18, giving you a growing season of approximately 124 days.
At an elevation of 7,123 feet, Roosevelt County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 78°F, so choose short-season varieties of Celeriac to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Celeriac successfully. Mulch heavily to conserve soil moisture.
Roosevelt County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.7
Drainage
Well Drained
Plant 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 Roosevelt County
How your county's soil matches Celeriac's growing requirements.
Soil pH
Your soil pH (6.7–7.7) is more alkaline than Celeriac prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Roosevelt County is excellent for Celeriac — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Celeriac.
How to Plant Celeriac
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Celeriac
Celeriac needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.
| Month | Celeriac Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.7" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | 3.9" | 2.3" | 1.6" | 💧 Light watering |
| Jun | 3.9" | 1.5" | 2.4" | 🚿 Regular watering |
| Jul | 3.9" | 1.6" | 2.3" | 🚿 Regular watering |
| Aug | 3.9" | 1.9" | 2" | 🚿 Regular watering |
| Sep | 3.9" | 1.7" | 2.2" | 🚿 Regular watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Roosevelt County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Celeriac 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.
Celeriac Planting Timeline — Roosevelt County, MT
Celeriac Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 17 | May 17 – May 31 |
| Direct Sow | May 10 | May 10 – May 31 |
| Harvest | August 30 | Aug 30 – Sep 20 |
| Fall Sowing | June 26 | Jun 26 – Jul 10 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Fall Sowing |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.9"/week · Only during dry spells
📅 Days to Maturity
100–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 3b
📆 Growing Season
124 days in Roosevelt County
Growing Tips for Celeriac in Roosevelt County
Direct sow Celeriac outdoors after May 17 in Roosevelt County when soil has warmed and frost danger has passed.
Your 124.0-day growing season in Roosevelt County is tight for Celeriac (100.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Celeriac in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.
Roosevelt County receives only 20" of rain annually. Celeriac needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 10-12 weeks before last frost. Remove side roots as they develop to encourage a single large bulb. Harvest after a light frost for best flavor.
Companion Planting
Good Companions
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Celeriac in Other Locations
Frequently Asked Questions
When should I plant Celeriac in Roosevelt County, MT?
Roosevelt County is in Zone 3b with an average last frost of May 17. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.
What planting zone is Roosevelt County, MT?
Roosevelt County, Montana is in USDA Hardiness Zone 3b. The average last spring frost is May 17 and first fall frost is September 18.
Plan Your Garden with Confidence
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