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When to Plant Lima Beans in Humboldt County, CA

Humboldt County, California Zone 9b May

Your May gardening checklist

Your Humboldt County, California garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost February 27
Avg. first frost November 28
Soil temp (4") 74°F
Watering Critical
Pest pressure High
Daylight 14.3 hrs
  1. Start harvesting lima beans

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this May that'll pay off in June
  • First harvests: 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.

Humboldt County, California is in USDA Zone 9b. The average last spring frost is February 27 and the first fall frost is November 28, giving you a growing season of approximately 274 days.

At an elevation of 148 feet, Humboldt County receives approximately 22.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 87°F, providing good warmth for Lima Beans during the growing season. Sandy soil warms quickly in spring — great for early planting — but Lima Beans will need more frequent watering and organic matter to retain nutrients.

Humboldt County, CA (Zone 9b) Year-round
274 days
Last Spring Frost February 27
274 growing days
First Fall Frost November 28

Humboldt County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (178 days to spare)
Transplant: Feb 13 🍅 Harvest: Apr 17 – May 29
Recommended (50%) ✓ Fits season (169 days to spare)
Transplant: Feb 27 🍅 Harvest: May 1 – Jun 12
Safe Start (90%) ✓ Fits season (155 days to spare)
Transplant: Apr 2 🍅 Harvest: Jun 4 – Jul 16

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 Humboldt County

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

Soil pH

Your soil pH (6.2–6.8) is within Lima Beans's preferred range (6.0–7.0).

Soil Texture

Sandy soil in Humboldt County warms quickly in spring but drains fast. Lima Beans will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Lima Beans.

How to Plant Lima Beans

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

Succession Planting Lima Beans

5
successive plantings in your 274-day season

Sow every 6.9 weeks. Last sowing by Aug 30 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.3″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,377 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 4.8" 0" ❄️ Dormant
Feb 3.9" 5" 0" ✅ Rainfall sufficient
Mar 3.9" 3.3" 0.6" 💧 Light watering
Apr 3.9" 1.7" 2.2" 🚿 Regular watering
May 3.9" 0.5" 3.4" 🚿 Regular watering
Jun 3.9" 0.1" 3.8" 🚿 Regular watering
Jul 3.9" 0" 3.9" 🚿 Regular watering
Aug 3.9" 0" 3.9" 🚿 Regular watering
Sep 3.9" 0.3" 3.6" 🚿 Regular watering
Oct 3.9" 0.8" 3.1" 🚿 Regular watering
Nov 3.9" 1.9" 2" 🚿 Regular watering
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Humboldt 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 ~1,144 GDD — county provides 4,193 GDD Excellent fit

Lima Beans Planting Timeline — Humboldt County, CA

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow March 6 Mar 6 – Mar 27
Harvest May 8 May 8 – Jun 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

274 days in Humboldt County

Growing Tips for Lima Beans in Humboldt County

Direct sow Lima Beans outdoors after February 27 in Humboldt County when soil has warmed and frost danger has passed.

Sandy soil in Humboldt County dries quickly — mulch Lima Beans with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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

Humboldt County receives only 22" 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 Humboldt County, CA?

Humboldt County is in Zone 9b with an average last frost of February 27. Plan your Lima Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Humboldt County, CA?

Humboldt County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 27 and first fall frost is November 28.

🌱

Your Humboldt County Garden Planner — Free

A 24-page printable planner built for Humboldt County (Zone 9b). 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 Humboldt County, CA. 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.