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When to Plant Lentils in Benton County, OR

Benton County, Oregon Zone 8b May

Your May gardening checklist

Each item below is timed to Benton County, Oregon's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 14
Avg. first frost October 30
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs
  1. Sow lentils in trays indoors

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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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.

Benton County, Oregon is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 30, giving you a growing season of approximately 199 days.

At an elevation of 97 feet, Benton County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Lentils during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Lentils root diseases.

Benton County, OR (Zone 8b) Moderate season
199 days
Last Spring Frost April 14
199 growing days
First Fall Frost October 30
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Benton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (85 days to spare)
Start indoors: Feb 20 Transplant: Mar 27 🍅 Harvest: Jun 19 – Jul 31
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jul 7 – Aug 18
Safe Start (90%) ✓ Fits season (80 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jul 30 – Sep 10

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 Benton County

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

Soil pH

Your soil pH (5.6–6.2) is more acidic than Lentils prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Lentils will thrive.

How to Plant Lentils

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 Lentils

2
successive plantings in your 199-day season

Sow every 9.1 weeks. Last sowing by Jul 12 to harvest before frost.

For a dedicated fall crop, sow by Aug 21.

Plant Water Budget

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

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 8.1" 0" ❄️ Dormant
Feb 6.1" 0" ❄️ Dormant
Mar 5.8" 0" ❄️ Dormant
Apr 2.6" 3.6" 0" ✅ Rainfall sufficient
May 2.6" 3.3" 0" ✅ Rainfall sufficient
Jun 2.6" 1.9" 0.7" 💧 Light watering
Jul 2.6" 0.9" 1.7" 🚿 Regular watering
Aug 2.6" 0.8" 1.8" 🚿 Regular watering
Sep 2.6" 2.3" 0.3" 💧 Light watering
Oct 2.6" 3.8" 0" ✅ Rainfall sufficient
Nov 8.3" 0" ❄️ Dormant
Dec 8.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Benton 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 ~1,306 GDD — county provides 2,736 GDD Excellent fit

Lentils Planting Timeline — Benton County, OR

Lentils Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest July 7 Jul 7 – Aug 18
Fall Sowing August 21 Aug 21 – Sep 4

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 8b

📆 Growing Season

199 days in Benton County

Growing Tips for Lentils in Benton County

Direct sow Lentils outdoors after April 14 in Benton County when soil has warmed and frost danger has passed.

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 Benton County, OR?

Benton County is in Zone 8b with an average last frost of April 14. Plan your Lentils planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benton County, OR?

Benton County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 30.

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Your Benton County Garden Planner — Free

A 24-page printable planner built for Benton County (Zone 8b). 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 Benton County, OR. 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.