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When to Plant Purslane in Alameda County, CA

Alameda County, California Zone 10a May

Your May planting checklist for Alameda County, California

May is a pivotal month for Alameda County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost January 18
Avg. first frost December 12
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 14 hrs

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Purslane is a succulent edible plant rich in omega-3 fatty acids, often considered a weed but increasingly valued as a nutritious green. It has a lemony, peppery flavor.

Alameda 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 379 feet, Alameda County receives approximately 16.4 inches of rainfall annually with predominantly loam soil. Summer highs average 97°F, so Purslane may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Purslane successfully. Mulch heavily to conserve soil moisture.

Alameda 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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Alameda County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (248 days to spare)
Start indoors: Dec 17 Transplant: Jan 14 🍅 Harvest: Feb 25 – Apr 1
Recommended (50%) ✓ Fits season (251 days to spare)
Start indoors: Dec 21 Transplant: Jan 18 🍅 Harvest: Mar 1 – Apr 5
Safe Start (90%) ✓ Fits season (198 days to spare)
Start indoors: Feb 24 Transplant: Mar 24 🍅 Harvest: May 5 – Jun 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 Alameda County

How your county's soil matches Purslane's growing requirements.

Soil pH

Your soil pH (6.3–7.7) overlaps with Purslane's range (5.5–7.5), though not a perfect match.

Soil Texture

The loam soil in Alameda County is excellent for Purslane — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Purslane.

How to Plant Purslane

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Purslane

10
successive plantings in your 328-day season

Sow every 4.6 weeks. Last sowing by Oct 13 to harvest before frost.

For a dedicated fall crop, sow by Oct 17.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,021 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Purslane

Purslane needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Purslane Needs Rainfall You Supplement Action
Jan 2.2" 3" 0" ✅ Rainfall sufficient
Feb 2.2" 3.6" 0" ✅ Rainfall sufficient
Mar 2.2" 2.6" 0" ✅ Rainfall sufficient
Apr 2.2" 1.2" 1" 💧 Light watering
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.2" 2" 🚿 Regular watering
Oct 2.2" 0.6" 1.6" 🚿 Regular watering
Nov 2.2" 1.5" 0.7" 💧 Light watering
Dec 2.2" 3.1" 0" ✅ Rainfall sufficient

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

Purslane 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.

Purslane needs ~1,138 GDD — county provides 7,484 GDD Excellent fit

Purslane Planting Timeline — Alameda County, CA

Purslane Planting Calendar

Activity When Date Range
Start Indoors December 21 Dec 21 – Jan 4
Transplant Outdoors January 18 Jan 18 – Feb 1
Direct Sow December 28 Dec 28 – Jan 18
Harvest March 1 Mar 1 – Apr 5
Fall Sowing October 17 Oct 17 – Oct 31

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

328 days in Alameda County

Growing Tips for Purslane in Alameda County

Direct sow Purslane outdoors after January 18 in Alameda County when soil has warmed and frost danger has passed.

With summer highs reaching 97°F in Alameda County, provide afternoon shade for Purslane and water deeply in the morning.

Your generous 329.0-day season in Alameda County allows multiple plantings of Purslane. Sow every 20.0 days for continuous harvest.

Alameda County receives only 16" of rain annually. Purslane needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost or allow to self-seed. Purslane thrives in hot, dry conditions. Harvest stem tips regularly. Contains more omega-3 fatty acids than any other leafy green.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Purslane in Alameda County, CA?

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

What planting zone is Alameda County, CA?

Alameda 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 Alameda County Garden Planner — Free

A 24-page printable planner built for Alameda 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 Alameda 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.