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When to Plant Yard Long Beans in Marin County, CA

Marin County, California Zone 9b May

Your May game plan for Marin County, California

A quick May briefing for Marin County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost February 26
Avg. first frost November 26
Soil temp (4") 79°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Start harvesting yard long beans

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

June will be here before you know it — start on
  • First harvests: yard long beans

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Yard long beans are a tropical legume that produces slender pods up to 24 inches long. They are a staple in Southeast Asian cooking and thrive in hot weather.

Marin County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.

At an elevation of 302 feet, Marin County receives approximately 36 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 81°F, so choose short-season varieties of Yard Long Beans to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Yard Long Beans will need more frequent watering and organic matter to retain nutrients.

Marin County, CA (Zone 9b) Year-round
273 days
Last Spring Frost February 26
273 growing days
First Fall Frost November 26

Marin County Soil Profile

Soil Type

Sandy Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (180 days to spare)
Start indoors: Dec 30 Transplant: Feb 17 🍅 Harvest: Apr 14 – May 26
Recommended (50%) ✓ Fits season (168 days to spare)
Start indoors: Jan 15 Transplant: Mar 5 🍅 Harvest: Apr 30 – Jun 11
Safe Start (90%) ✓ Fits season (154 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🍅 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 Marin County

How your county's soil matches Yard Long Beans's growing requirements.

Soil pH

Your soil pH (6.0–6.9) is within Yard Long Beans's preferred range (6.0–7.5).

Soil Texture

Sandy soil in Marin County warms quickly in spring but drains fast. Yard Long 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 Yard Long Beans.

How to Plant Yard Long Beans

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

Succession Planting Yard Long Beans

5
successive plantings in your 273-day season

Sow every 6.3 weeks. Last sowing by Sep 07 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,312 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Yard Long Beans

Yard Long Beans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Yard Long Beans Needs Rainfall You Supplement Action
Jan 7.2" 0" ❄️ Dormant
Feb 4.3" 6.5" 0" ✅ Rainfall sufficient
Mar 4.3" 6.2" 0" ✅ Rainfall sufficient
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 1" 3.3" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 4.3" 3.5" 0.8" 💧 Light watering
Dec 6.9" 0" ❄️ Dormant

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

Yard Long 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.

Yard Long Beans needs ~726 GDD — county provides 2,945 GDD Excellent fit

Yard Long Beans Planting Timeline — Marin County, CA

Yard Long Beans Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow February 26 Feb 26 – Mar 19
Harvest April 30 Apr 30 – Jun 11

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

55–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

273 days in Marin County

Growing Tips for Yard Long Beans in Marin County

Direct sow Yard Long Beans outdoors after February 26 in Marin County when soil has warmed and frost danger has passed.

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

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

General growing tips

Direct sow after soil is warm. Provide tall poles or trellising as vines can reach 8-10 feet. Harvest when pods are pencil-thick before seeds bulge. Cook quickly for best texture.

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 Yard Long Beans in Marin County, CA?

Marin County is in Zone 9b with an average last frost of February 26. Plan your Yard Long Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marin County, CA?

Marin County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 26 and first fall frost is November 26.

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Your Marin County Garden Planner — Free

A 24-page printable planner built for Marin 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 Marin 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.