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When to Plant Kidney Beans in San Diego County, CA

San Diego County, California Zone 10b April

April in the garden — San Diego County, California

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

Avg. last frost April 16
Avg. first frost November 1
Soil temp (4") 66°F
Watering High
Pest pressure High
Daylight 12.8 hrs
  1. Seed kidney beans outdoors

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

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Kidney beans are a popular dry bean variety named for their shape, available in red and white types. They are the classic bean for chili and red beans and rice.

San Diego County, California is in USDA Zone 10b. The average last spring frost is April 16 and the first fall frost is November 1, giving you a growing season of approximately 199 days.

At an elevation of 2,613 feet, San Diego County receives approximately 18.2 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Kidney Beans during the growing season. With low rainfall, drip irrigation is essential for growing Kidney Beans successfully. Mulch heavily to conserve soil moisture.

San Diego County, CA (Zone 10b) Moderate season
199 days
Last Spring Frost April 16
199 growing days
First Fall Frost November 1
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San Diego County Soil Profile

Soil Type

Loam

Soil pH

5.7-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (68 days to spare)
Transplant: Apr 9 🍅 Harvest: Jul 9 – Aug 13
Recommended (50%) ✓ Fits season (73 days to spare)
Transplant: Apr 16 🍅 Harvest: Jul 16 – Aug 20
Safe Start (90%) ✓ Fits season (69 days to spare)
Transplant: May 21 🍅 Harvest: Aug 20 – Sep 24

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 San Diego County

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

Soil pH

Your soil pH (5.7–7.5) overlaps with Kidney Beans's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in San Diego County is excellent for Kidney Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Kidney Beans.

How to Plant Kidney Beans

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,309 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Kidney Beans

Kidney 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 Kidney Beans Needs Rainfall You Supplement Action
Jan 3" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 4.3" 1.4" 2.9" 🚿 Regular watering
May 4.3" 0.5" 3.8" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.2" 4.1" 🚿 Regular watering
Oct 4.3" 0.8" 3.5" 🚿 Regular watering
Nov 4.3" 1.8" 2.5" 🚿 Regular watering
Dec 3.3" 0" ❄️ Dormant

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

Kidney 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.

Kidney Beans needs ~1,852 GDD — county provides 3,781 GDD Excellent fit

Kidney Beans Planting Timeline — San Diego County, CA

Kidney Beans Planting Calendar

Activity When Date Range
Direct Sow April 23 Apr 23 – May 14
Harvest July 23 Jul 23 – Aug 27

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

85–110 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 10b

📆 Growing Season

199 days in San Diego County

Growing Tips for Kidney Beans in San Diego County

Direct sow Kidney Beans outdoors after April 16 in San Diego County when soil has warmed and frost danger has passed.

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

San Diego County receives only 18" of rain annually. Kidney Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after frost. Allow pods to dry completely on the plant. Kidney beans must be thoroughly cooked as raw or undercooked beans contain harmful lectins.

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 Kidney Beans in San Diego County, CA?

San Diego County is in Zone 10b with an average last frost of April 16. Plan your Kidney Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Diego County, CA?

San Diego County, California is in USDA Hardiness Zone 10b. The average last spring frost is April 16 and first fall frost is November 1.

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Your San Diego County Garden Planner — Free

A 24-page printable planner built for San Diego County (Zone 10b). 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 San Diego County, CA. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.