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When to plant Leeks in Foothill Ranch,

Leeks planted in Foothill Ranch between January 23 and February 13 matures in 150 days — well before the December 11 first frost. A second sowing from October 16 to October 30 extends the harvest into fall.

When to Plant Leeks in Foothill Ranch, CA

Leeks
Foothill Ranch, CA Zone 10b June

What to do in June

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Foothill Ranch, CA.

Avg. last frost February 13
Avg. first frost December 11
Soil temp (4") 86°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Pick leeks

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

July prep starts now
  • 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.

Foothill Ranch, California is in USDA Zone 10b. The average last spring frost is February 13 and the first fall frost is December 11, giving you a growing season of approximately 301 days.

At an elevation of 405 feet, Orange County receives approximately 13.8 inches of rainfall annually with predominantly loam soil. Summer highs average 88°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.

Foothill Ranch, CA (Zone 10b) Year-round
301 days
Last Spring Frost February 13
301 growing days
First Fall Frost December 11

Foothill Ranch Soil Profile

Soil Type

Loam

Soil pH

5.7-7.6

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✓ Fits season (132 days to spare)
Start indoors: Jan 5 Transplant: Feb 2 🍅 Harvest: May 4 – Jul 20
Recommended (50%) ✓ Fits season (133 days to spare)
Start indoors: Jan 16 Transplant: Feb 13 🍅 Harvest: May 15 – Jul 31
Safe Start (90%) ✓ Fits season (94 days to spare)
Start indoors: Mar 5 Transplant: Apr 2 🍅 Harvest: Jul 2 – Sep 17

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 Foothill Ranch

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

Soil pH

Your soil pH (5.7–7.6) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). 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 1,961 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 2.4" 0" ❄️ Dormant
Feb 3.5" 2.6" 0.9" 💧 Light watering
Mar 3.5" 2.2" 1.3" 💧 Light watering
Apr 3.5" 1.1" 2.4" 🚿 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" 1.5" 2" 🚿 Regular watering
Dec 3.5" 2.7" 0.8" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Orange 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 ~1,920 GDD — county provides 4,832 GDD Excellent fit

Leeks Planting Timeline — Foothill Ranch, CA

Leeks Planting Calendar

Activity When Date Range
Start Indoors January 16 Jan 16 – Jan 30
Transplant Outdoors February 13 Feb 13 – Feb 27
Direct Sow January 23 Jan 23 – Feb 13
Harvest May 15 May 15 – Jul 31
Fall Sowing October 16 Oct 16 – Oct 30

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: acceptable

🗺️ USDA Zone

Zone 10b

📆 Growing Season

301 days in Orange County

Growing Tips for Leeks in Foothill Ranch

Direct sow Leeks outdoors after February 13 in Orange 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 Foothill Ranch, ?

In Foothill Ranch, , plant Leeks after the last frost (around February 13) and before the first frost (around December 11). Best results when soil holds above 50°F.

What growing zone is Foothill Ranch, for Leeks?

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

Can Leeks grow in Foothill Ranch's climate?

Yes — Leeks grows well in Foothill Ranch's temperate climate. Foothill Ranch averages a 302-day frost-free season, with last frost around February 13 and first frost around December 11.

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Your Orange County Garden Planner — Free

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