When to Plant Leeks in Park County, MT
May in Park County, Montana — your action list
Your garden in Park County, Montana is working on a schedule, even when you're not. Here's where you should be this May.
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Move leeks from tray to bed
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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Plant leeks from seed, right in the garden
Mark the row. Birds and stray feet both have opinions about unmarked beds.
Looking ahead to June
- Starting indoors: leeks
Leeks are a mild, sweet allium that produces long white shanks. They are more refined than onions and are a key ingredient in soups, stews, and gratins.
Park County, Montana is in USDA Zone 5a. The average last spring frost is May 24 and the first fall frost is September 20, giving you a growing season of approximately 119 days.
At an elevation of 6,994 feet, Park County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Leeks to ensure they mature before fall.
Park County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.6
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 Park County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.5–7.6) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Park County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.8%). Annual compost additions will help Leeks.
How to Plant Leeks
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 Leeks
Leeks needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Leeks Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | — | 2.4" | 0" | ❄️ Dormant |
| May | 3.5" | 2.5" | 1" | 💧 Light watering |
| Jun | 3.5" | 1.7" | 1.8" | 🚿 Regular watering |
| Jul | 3.5" | 1.8" | 1.7" | 💧 Light watering |
| Aug | 3.5" | 2.3" | 1.2" | 💧 Light watering |
| Sep | 3.5" | 2" | 1.5" | 💧 Light 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 Park County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Leeks 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.
Leeks Planting Timeline — Park County, MT
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 19 | Apr 19 – May 3 |
| Transplant Outdoors | May 24 | May 24 – Jun 7 |
| Direct Sow | May 10 | May 10 – May 31 |
| Harvest | August 23 | Aug 23 – Nov 8 |
| Fall Sowing | July 12 | Jul 12 – Jul 26 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors Transplant Outdoors Direct Sow |
| June | Transplant Outdoors |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Only during dry spells
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
119 days in Park County
Growing Tips for Leeks in Park County
Direct sow Leeks outdoors after May 24 in Park County when soil has warmed and frost danger has passed.
Your 119.0-day growing season in Park County is tight for Leeks (90.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Leeks in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 10-12 weeks before last frost. Transplant into trenches and hill soil around stems as they grow to increase the white portion. Harvest as needed.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
Frequently Asked Questions
When should I plant Leeks in Park County, MT?
Park County is in Zone 5a with an average last frost of May 24. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Park County, MT?
Park County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 24 and first fall frost is September 20.
Your Park County Garden Planner — Free
A 24-page printable planner built for Park 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.