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When to Plant Lentils in Lewis and Clark County, MT

Lewis and Clark County, Montana Zone 4b May

Your May planting checklist for Lewis and Clark County, Montana

May is a pivotal month for Lewis and Clark County, Montana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 29
Avg. first frost September 18
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Time to transplant lentils

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

  2. Outdoor sowing time: lentils

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

To set up a strong June, finish these tasks
  • Fall sowing: lentils

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Lentils are an ancient pulse crop producing small, lens-shaped seeds packed with protein and iron. They grow on short, bushy plants and are surprisingly easy to cultivate.

Lewis and Clark County, Montana is in USDA Zone 4b. The average last spring frost is May 29 and the first fall frost is September 18, giving you a growing season of approximately 112 days.

At an elevation of 7,064 feet, Lewis and Clark County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Lentils to ensure they mature before fall.

Lewis and Clark County, MT (Zone 4b) Short season
112 days
Last Spring Frost May 29
112 growing days
First Fall Frost September 18

Lewis and Clark County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Aug 10 – Sep 21
Recommended (50%) ✗ May not fit
Start indoors: Apr 17 Transplant: May 29 🍅 Harvest: Aug 21 – Oct 2
Safe Start (90%) ✗ May not fit
Start indoors: May 8 Transplant: Jun 19 🍅 Harvest: Sep 11 – Oct 23

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 Lewis and Clark County

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

Soil pH

Your soil pH (6.5–8.1) overlaps with Lentils's range (6.0–8.0), though not a perfect match.

Soil Texture

The loam soil in Lewis and Clark County is excellent for Lentils — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Lentils.

How to Plant Lentils

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Lentils

Lentils 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 Lentils Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.3" 0" ❄️ Dormant
May 2.6" 2.6" 0" ✅ Rainfall sufficient
Jun 2.6" 1.5" 1.1" 💧 Light watering
Jul 2.6" 1.9" 0.7" 💧 Light watering
Aug 2.6" 2.3" 0.3" 💧 Light watering
Sep 2.6" 1.8" 0.8" 💧 Light watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Lentils 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.

Lentils needs ~1,092 GDD — county provides 1,288 GDD Good fit

Lentils Planting Timeline — Lewis and Clark County, MT

Lentils Planting Calendar

Activity When Date Range
Start Indoors April 17 Apr 17 – May 1
Transplant Outdoors May 29 May 29 – Jun 12
Direct Sow May 22 May 22 – Jun 12
Harvest August 21 Aug 21 – Oct 2
Fall Sowing June 26 Jun 26 – Jul 10

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 Fall Sowing
July Fall Sowing
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

112 days in Lewis and Clark County

Growing Tips for Lentils in Lewis and Clark County

Direct sow Lentils outdoors after May 29 in Lewis and Clark County when soil has warmed and frost danger has passed.

Your 112.0-day growing season in Lewis and Clark County is tight for Lentils (80.0-110.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Lentils in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early spring as lentils tolerate frost. Provide short supports as plants tend to lodge. Harvest when lower pods turn brown. Pull entire plants and dry in bundles.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lentils in Lewis and Clark County, MT?

Lewis and Clark County is in Zone 4b with an average last frost of May 29. Plan your Lentils planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lewis and Clark County, MT?

Lewis and Clark County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 29 and first fall frost is September 18.

🌱

Your Lewis and Clark County Garden Planner — Free

A 24-page printable planner built for Lewis and Clark 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.

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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 Lewis and Clark 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.