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When to plant Leeks in Ripon, CA

Aim to plant Leeks in Ripon on or after January 14; the window stays open through February 4. Ripon's 306-day frost-free season gives you plenty of room for a spring and fall cycle. A second sowing from October 11 to October 25 extends the harvest into fall.

When to Plant Leeks in Ripon, CA

Leeks
San Joaquin County, California Zone 9b June

June to-do list for San Joaquin County, California

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

Avg. last frost February 4
Avg. first frost December 6
Soil temp (4") 84°F
Watering Critical
Pest pressure High
Daylight 14.6 hrs
  1. Pick leeks

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

A few tasks this June that'll pay off in July
  • First harvests: leeks

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Leeks are a mild, sweet allium that produces long white shanks. They are more refined than onions and are a key ingredient in soups, stews, and gratins.

Ripon, California is in USDA Zone 9b. The average last spring frost is February 4 and the first fall frost is December 6, giving you a growing season of approximately 305 days.

At an elevation of 220 feet, San Joaquin County receives approximately 15 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Leeks during the growing season. With low rainfall, drip irrigation is essential for growing Leeks successfully. Mulch heavily to conserve soil moisture.

Ripon, CA (Zone 9b) Year-round
305 days
Last Spring Frost February 4
305 growing days
First Fall Frost December 6

Ripon Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✓ Fits season (147 days to spare)
Start indoors: Dec 21 Transplant: Jan 18 🍅 Harvest: Apr 19 – Jul 5
Recommended (50%) ✓ Fits season (137 days to spare)
Start indoors: Jan 7 Transplant: Feb 4 🍅 Harvest: May 6 – Jul 22
Safe Start (90%) ✓ Fits season (121 days to spare)
Start indoors: Feb 5 Transplant: Mar 5 🍅 Harvest: Jun 4 – Aug 20

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 Ripon

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

Soil pH

Your soil pH (6.4–7.8) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Leeks.

How to Plant Leeks

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

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

Leeks Water Budget

Plant needs
0.8″/week
Rainfall provides
0.2″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,942 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Leeks

Leeks needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Leeks Needs Rainfall You Supplement Action
Jan 2.9" 0" ❄️ Dormant
Feb 3.5" 3.1" 0.4" 💧 Light watering
Mar 3.5" 2.6" 0.9" 💧 Light watering
Apr 3.5" 1.2" 2.3" 🚿 Regular watering
May 3.5" 0.4" 3.1" 🚿 Regular watering
Jun 3.5" 0.1" 3.4" 🚿 Regular watering
Jul 3.5" 0" 3.5" 🚿 Regular watering
Aug 3.5" 0" 3.5" 🚿 Regular watering
Sep 3.5" 0.2" 3.3" 🚿 Regular watering
Oct 3.5" 0.7" 2.8" 🚿 Regular watering
Nov 3.5" 1.3" 2.2" 🚿 Regular watering
Dec 3.5" 2.6" 0.9" 💧 Light watering

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

Leeks 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.

Leeks needs ~2,370 GDD — county provides 6,043 GDD Excellent fit

Leeks Planting Timeline — Ripon, CA

Leeks Planting Calendar

Activity When Date Range
Start Indoors January 7 Jan 7 – Jan 21
Transplant Outdoors February 4 Feb 4 – Feb 18
Direct Sow January 14 Jan 14 – Feb 4
Harvest May 6 May 6 – Jul 22
Fall Sowing October 11 Oct 11 – Oct 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 2-3 times/week

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

305 days in San Joaquin County

Growing Tips for Leeks in Ripon

Direct sow Leeks outdoors after February 04 in San Joaquin County when soil has warmed and frost danger has passed.

Common pests for Leeks in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 10-12 weeks before last frost. Transplant into trenches and hill soil around stems as they grow to increase the white portion. Harvest as needed.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

When should I plant Leeks in Ripon, CA?

In Ripon, CA, plant Leeks after the last frost (around February 4) and before the first frost (around December 6). Best results when soil holds above 50°F.

What growing zone is Ripon, CA for Leeks?

Ripon sits in USDA Zone 9b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Ripon's climate?

Yes — Leeks grows well in Ripon's temperate climate. Ripon averages a 306-day frost-free season, with last frost around February 4 and first frost around December 6.

🌱

Your San Joaquin County Garden Planner — Free

A 22-page printable planner built for San Joaquin 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 San Joaquin County, CA. Local conditions may vary. Last updated: June 2026.