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When to Plant Wax Beans in San Mateo County, CA

San Mateo County, California Zone 10a May

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Avg. last frost January 18
Avg. first frost December 12
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Bring in the wax beans

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

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Wax beans are a yellow-podded variety of snap beans with a buttery, slightly sweeter flavor than green beans. They are easy to spot on the plant for picking.

San Mateo County, California is in USDA Zone 10a. The average last spring frost is January 18 and the first fall frost is December 12, giving you a growing season of approximately 328 days.

At an elevation of 277 feet, San Mateo County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Wax Beans to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Wax Beans successfully. Mulch heavily to conserve soil moisture.

San Mateo County, CA (Zone 10a) Year-round
328 days
Last Spring Frost January 18
328 growing days
First Fall Frost December 12
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San Mateo County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (213 days to spare)
Transplant: Jan 14 🍅 Harvest: Mar 11 – May 6
Recommended (50%) ✓ Fits season (216 days to spare)
Transplant: Jan 18 🍅 Harvest: Mar 15 – May 10
Safe Start (90%) ✓ Fits season (163 days to spare)
Transplant: Mar 24 🍅 Harvest: May 19 – Jul 14

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 Mateo County

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

Soil pH

Your soil pH (6.8–7.2) overlaps with Wax Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Wax Beans.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Wax Beans.

How to Plant Wax Beans

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

Succession Planting Wax Beans

7
successive plantings in your 328-day season

Sow every 5.7 weeks. Last sowing by Oct 08 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 3,810 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Wax Beans

Wax 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 Wax Beans Needs Rainfall You Supplement Action
Jan 4.3" 3.9" 0.4" 💧 Light watering
Feb 4.3" 3.4" 0.9" 💧 Light watering
Mar 4.3" 2.7" 1.6" 💧 Light watering
Apr 4.3" 1.2" 3.1" 🚿 Regular watering
May 4.3" 0.4" 3.9" 🚿 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" 0.7" 3.6" 🚿 Regular watering
Nov 4.3" 1.4" 2.9" 🚿 Regular watering
Dec 4.3" 2.9" 1.4" 💧 Light watering

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

Wax 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.

Wax Beans needs ~618 GDD — county provides 3,536 GDD Excellent fit

Wax Beans Planting Timeline — San Mateo County, CA

Wax Beans Planting Calendar

Activity When Date Range
Direct Sow January 25 Jan 25 – Feb 15
Harvest March 22 Mar 22 – May 17

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

Month-by-Month Timeline

MonthActivities
January Direct Sow
February Direct Sow
March Harvest
April Harvest
May Harvest
June
July
August
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

50–65 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

328 days in San Mateo County

Growing Tips for Wax Beans in San Mateo County

Direct sow Wax Beans outdoors after January 18 in San Mateo County when soil has warmed and frost danger has passed.

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

San Mateo County receives only 17" of rain annually. Wax Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost. Pick pods regularly when young and tender. Bush types produce a concentrated harvest while pole types yield longer. Avoid working around wet plants.

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 Wax Beans in San Mateo County, CA?

San Mateo County is in Zone 10a with an average last frost of January 18. Plan your Wax Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Mateo County, CA?

San Mateo County, California is in USDA Hardiness Zone 10a. The average last spring frost is January 18 and first fall frost is December 12.

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Your San Mateo County Garden Planner — Free

A 24-page printable planner built for San Mateo County (Zone 10a). 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 Mateo 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.