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When to plant Leeks in Isleton,

Plant Leeks in Isleton from January 22 to February 12 in spring. Isleton sits in USDA Zone 9b, with last frost around February 12 and first frost on December 1. A second sowing from October 6 to October 20 extends the harvest into fall.

When to Plant Leeks in Isleton, CA

Leeks
Sacramento County, California Zone 9b June

What to do in June

Your Sacramento County, California garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost February 12
Avg. first frost December 1
Soil temp (4") 87°F
Watering Critical
Pest pressure High
Daylight 14.7 hrs
  1. Harvest leeks as they ripen

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

Before July arrives, get these ready
  • 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.

Isleton, California is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 1, giving you a growing season of approximately 292 days.

At an elevation of 263 feet, Sacramento County receives approximately 33.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Leeks during the growing season.

Isleton, CA (Zone 9b) Year-round
292 days
Last Spring Frost February 12
292 growing days
First Fall Frost December 1

Isleton Soil Profile

Soil Type

Loam

Soil pH

6.4-7.1

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✓ Fits season (135 days to spare)
Start indoors: Dec 29 Transplant: Jan 26 🍅 Harvest: Apr 27 – Jul 13
Recommended (50%) ✓ Fits season (124 days to spare)
Start indoors: Jan 15 Transplant: Feb 12 🍅 Harvest: May 14 – Jul 30
Safe Start (90%) ✓ Fits season (90 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: Jul 6 – Sep 21

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 Isleton

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

Soil pH

Your soil pH (6.4–7.1) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). 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
0.5″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,014 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 6.1" 0" ❄️ Dormant
Feb 3.5" 7.5" 0" ✅ Rainfall sufficient
Mar 3.5" 5.7" 0" ✅ Rainfall sufficient
Apr 3.5" 2.5" 1" 💧 Light watering
May 3.5" 0.8" 2.7" 🚿 Regular watering
Jun 3.5" 0.2" 3.3" 🚿 Regular watering
Jul 3.5" 0" 3.5" 🚿 Regular watering
Aug 3.5" 0" 3.5" 🚿 Regular watering
Sep 3.5" 0.3" 3.2" 🚿 Regular watering
Oct 3.5" 1.4" 2.1" 🚿 Regular watering
Nov 3.5" 2.7" 0.8" 💧 Light watering
Dec 3.5" 5.9" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Sacramento 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 ~2,100 GDD — county provides 5,127 GDD Excellent fit

Leeks Planting Timeline — Isleton, CA

Leeks Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors February 12 Feb 12 – Feb 26
Direct Sow January 22 Jan 22 – Feb 12
Harvest May 14 May 14 – Jul 30
Fall Sowing October 6 Oct 6 – Oct 20

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 · 1-2 times/week

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

292 days in Sacramento County

Growing Tips for Leeks in Isleton

Direct sow Leeks outdoors after February 12 in Sacramento 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 Isleton, ?

In Isleton, , plant Leeks after the last frost (around February 12) and before the first frost (around December 1). Best results when soil holds above 50°F.

What growing zone is Isleton, for Leeks?

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

Can Leeks grow in Isleton's climate?

Yes — Leeks grows well in Isleton's temperate climate. Isleton averages a 293-day frost-free season, with last frost around February 12 and first frost around December 1.

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