When to Plant Parsley in Jefferson County, MT
This month in Jefferson County, Montana
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Jefferson County, Montana.
Coming up in June — start thinking about
- Transplants going out: parsley
- Direct-sowing: parsley
- Fall sowing: parsley
Parsley is a biennial herb available in flat-leaf (Italian) and curly varieties. It is a nutritional powerhouse rich in vitamins C and K and adds fresh flavor to countless dishes.
Jefferson County, Montana is in USDA Zone 5a. The average last spring frost is June 15 and the first fall frost is September 7, giving you a growing season of approximately 84 days.
At an elevation of 7,214 feet, Jefferson County receives approximately 21.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Parsley to ensure they mature before fall.
Jefferson County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.9
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 Jefferson County
How your county's soil matches Parsley's growing requirements.
Soil pH
Your soil pH (6.4–7.9) is more alkaline than Parsley prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Jefferson County is excellent for Parsley — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Parsley.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Parsley.
How to Plant Parsley
Fall planting: Sow 10 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 Parsley
Parsley needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Parsley Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | — | 2.5" | 0" | ❄️ Dormant |
| Jun | 2.6" | 1.5" | 1.1" | 💧 Light watering |
| Jul | 2.6" | 2" | 0.6" | 💧 Light watering |
| Aug | 2.6" | 2" | 0.6" | 💧 Light watering |
| Sep | 2.6" | 2" | 0.6" | 💧 Light watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Parsley 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.
Parsley Planting Timeline — Jefferson County, MT
Parsley Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 11 | May 11 – May 25 |
| Transplant Outdoors | June 8 | Jun 8 – Jun 22 |
| Direct Sow | June 1 | Jun 1 – Jun 22 |
| Harvest | August 10 | Aug 10 – Oct 12 |
| Fall Sowing | June 29 | Jun 29 – Jul 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.6"/week · Natural rainfall sufficient
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
84 days in Jefferson County
Growing Tips for Parsley in Jefferson County
Direct sow Parsley outdoors after June 15 in Jefferson County when soil has warmed and frost danger has passed.
Your 84.0-day growing season in Jefferson County is tight for Parsley (60.0-80.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Parsley in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 6-8 weeks before last frost. Soak seeds overnight as germination is slow. Harvest outer stems first to keep plants productive. Parsley attracts swallowtail butterflies.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Parsley in Other Locations
Frequently Asked Questions
When should I plant Parsley in Jefferson County, MT?
Jefferson County is in Zone 5a with an average last frost of June 15. Plan your Parsley planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, MT?
Jefferson County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 15 and first fall frost is September 7.
Your Jefferson County Garden Planner — Free
A 24-page printable planner built for Jefferson County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.