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When to Plant Lettuce in Lake County, MT

Lake County, Montana Zone 6a May

May in Lake County, Montana — your action list

We've pulled the most time-sensitive tasks for Lake County, Montana this May and put them front and centre. Tackle them in order.

Avg. last frost May 31
Avg. first frost September 12
Soil temp (4") 36°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Move lettuce from tray to bed

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Scatter lettuce into prepared beds

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

Lake County, Montana is in USDA Zone 6a. The average last spring frost is May 31 and the first fall frost is September 12, giving you a growing season of approximately 104 days.

At an elevation of 6,938 feet, Lake County receives approximately 12.8 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Lettuce during the growing season. With low rainfall, drip irrigation is essential for growing Lettuce successfully. Mulch heavily to conserve soil moisture.

Lake County, MT (Zone 6a) Short season
104 days
Last Spring Frost May 31
104 growing days
First Fall Frost September 12
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Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Jun 24 – Sep 2
Recommended (50%) ✗ May not fit
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Jul 5 – Sep 13
Safe Start (90%) ✓ Fits season (0 days to spare)
Start indoors: May 17 Transplant: Jun 21 🍅 Harvest: Jul 26 – Oct 4

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 Lake County

How your county's soil matches Lettuce's growing requirements.

Soil pH

Your soil pH (6.6–7.7) is more alkaline than Lettuce prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Lake County is excellent for Lettuce — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Lettuce.

How to Plant Lettuce

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Lettuce

4
successive plantings in your 104-day season

Sow every 3.4 weeks. Last sowing by Jul 14 to harvest before frost.

For a dedicated fall crop, sow by Jul 04.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 203 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lettuce

Lettuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Lettuce Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 3" 1.4" 1.6" 🚿 Regular watering
Jun 3" 0.9" 2.1" 🚿 Regular watering
Jul 3" 1.3" 1.7" 🚿 Regular watering
Aug 3" 1.2" 1.8" 🚿 Regular watering
Sep 3" 1.1" 1.9" 🚿 Regular watering
Oct 1.1" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Lake County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Lettuce 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.

Lettuce needs ~619 GDD — county provides 1,430 GDD Excellent fit

Lettuce Planting Timeline — Lake County, MT

Lettuce Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 – May 10
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 17 May 17 – Jun 7
Harvest July 5 Jul 5 – Sep 13
Fall Sowing July 4 Jul 4 – Jul 18

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

104 days in Lake County

Growing Tips for Lettuce in Lake County

Direct sow Lettuce outdoors after May 31 in Lake County when soil has warmed and frost danger has passed.

Common pests for Lettuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Recommended Lettuce Varieties for Lake County

Bolt-resistant varieties for warm summers — grow as spring/fall crop

Jericho Muir Nevada New Red Fire

Fast-maturing leaf and butterhead types

Salad Bowl (40d) Black Seeded Simpson (45d) Buttercrunch (50d)

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35°F, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Lake County, MT?

Lake County is in Zone 6a with an average last frost of May 31. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, MT?

Lake County, Montana is in USDA Hardiness Zone 6a. The average last spring frost is May 31 and first fall frost is September 12.

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Your Lake County Garden Planner — Free

A 24-page printable planner built for Lake County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lake County, MT. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.