When to Plant Leeks in Fallon County, MT
Top priorities for Fallon County, Montana gardeners in May
A quick May briefing for Fallon County, Montana gardeners — what's urgent, what's next, and what can wait.
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Time to transplant leeks
Frost risk is low now in Fallon County, Montana. If you've been covering beds overnight, you can stop.
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Scatter leeks into prepared beds
Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.
June prep starts now
- Fall sowing: 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.
Fallon County, Montana is in USDA Zone 4b. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.
At an elevation of 6,441 feet, Fallon County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Leeks to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Leeks successfully. Mulch heavily to conserve soil moisture.
Fallon County Soil Profile
Soil Type
Loam
Soil pH
6.2-8.3
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 Fallon County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.2–8.3) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Fallon County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Leeks.
How to Plant Leeks
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 6/10 — 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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 3.5" | 2.7" | 0.8" | 💧 Light watering |
| Jun | 3.5" | 1.4" | 2.1" | 🚿 Regular watering |
| Jul | 3.5" | 1.6" | 1.9" | 🚿 Regular watering |
| Aug | 3.5" | 1.9" | 1.6" | 💧 Light watering |
| Sep | 3.5" | 1.6" | 1.9" | 🚿 Regular watering |
| Oct | — | 1.7" | 0" | ❄️ Dormant |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Fallon 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 — Fallon County, MT
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 8 | Apr 8 – Apr 22 |
| Transplant Outdoors | May 20 | May 20 – Jun 3 |
| Direct Sow | May 13 | May 13 – Jun 3 |
| Harvest | August 19 | Aug 19 – Oct 14 |
| Fall Sowing | June 28 | Jun 28 – Jul 12 |
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 | Transplant Outdoors Direct Sow Fall Sowing |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| 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 4b
📆 Growing Season
123 days in Fallon County
Growing Tips for Leeks in Fallon County
Direct sow Leeks outdoors after May 20 in Fallon County when soil has warmed and frost danger has passed.
Your 123.0-day growing season in Fallon 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 Fallon County, MT?
Fallon County is in Zone 4b with an average last frost of May 20. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Fallon County, MT?
Fallon County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 20 and first fall frost is September 20.
Your Fallon County Garden Planner — Free
A 24-page printable planner built for Fallon County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.