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When to Plant Lima Beans in Grant County, OR

Grant County, Oregon Zone 6b May

May in the garden — Grant County, Oregon

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

Avg. last frost June 6
Avg. first frost September 10
Soil temp (4") 51°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
June will be here before you know it — start on
  • Direct-sowing: lima beans

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Lima beans are a warm-season legume producing large, creamy beans with a buttery texture. Both bush and pole varieties are available, with pole types yielding more.

Grant County, Oregon is in USDA Zone 6b. The average last spring frost is June 6 and the first fall frost is September 10, giving you a growing season of approximately 96 days.

At an elevation of 2,838 feet, Grant County receives approximately 22.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Lima Beans to ensure they mature before fall.

Grant County, OR (Zone 6b) Very short season
96 days
Last Spring Frost June 6
96 growing days
First Fall Frost September 10
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Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 20 🍅 Harvest: Jul 22 – Sep 2
Recommended (50%) ✗ May not fit
Transplant: Jun 6 🍅 Harvest: Aug 8 – Sep 19
Safe Start (90%) ✗ May not fit
Transplant: Jun 26 🍅 Harvest: Aug 28 – Oct 9

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 Grant County

How your county's soil matches Lima Beans's growing requirements.

Soil pH

Your soil pH (5.4–6.4) is more acidic than Lima Beans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Lima Beans.

Organic Matter

Organic matter is excellent (4.8%) — Lima Beans will thrive.

How to Plant Lima Beans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.0″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 155 gal / 100 sq ft

Monthly Watering Guide for Lima Beans

Lima Beans needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Lima Beans Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 1.3" 0" ❄️ Dormant
Jun 3.9" 0.8" 3.1" 🚿 Regular watering
Jul 3.9" 0.4" 3.5" 🚿 Regular watering
Aug 3.9" 0.4" 3.5" 🚿 Regular watering
Sep 3.9" 0.9" 3" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 3.1" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

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

Lima Beans 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.

Lima Beans needs ~919 GDD — county provides 1,176 GDD Good fit

Lima Beans Planting Timeline — Grant County, OR

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow June 13 Jun 13 – Jul 4
Harvest August 15 Aug 15 – Sep 26

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Direct Sow
July Direct Sow
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

96 days in Grant County

Growing Tips for Lima Beans in Grant County

Direct sow Lima Beans outdoors after June 06 in Grant County when soil has warmed and frost danger has passed.

Your 96.0-day growing season in Grant County is tight for Lima Beans (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Grant County receives only 23" of rain annually. Lima Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil is thoroughly warm at 65F or above. Do not soak seeds before planting as they may crack. Harvest when pods are plump but still green for fresh limas.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lima Beans in Grant County, OR?

Grant County is in Zone 6b with an average last frost of June 6. Plan your Lima Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, OR?

Grant County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is June 6 and first fall frost is September 10.

🌱

Your Grant County Garden Planner — Free

A 24-page printable planner built for Grant County (Zone 6b). 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 Grant 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.