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When to plant Leeks in Humboldt County, CA

Humboldt County's spring Leeks window runs February 6 through February 27. aim for a steady week of warm soil before planting. A second sowing from October 3 to October 17 extends the harvest into fall.

When to Plant Leeks in Humboldt County, CA

Leeks

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.

Humboldt County, California is in USDA Zone 9b. The average last spring frost is February 27 and the first fall frost is November 28, giving you a growing season of approximately 274 days.

At an elevation of 148 feet, Humboldt County receives approximately 22.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 87°F, providing good warmth for Leeks during the growing season. Sandy soil warms quickly in spring — great for early planting — but Leeks will need more frequent watering and organic matter to retain nutrients.

Humboldt County, CA (Zone 9b) Year-round
274 days
Last Spring Frost February 27
274 growing days
First Fall Frost November 28

Humboldt County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Monthly Watering Guide for Leeks

Leeks needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Leeks Needs Rainfall You Supplement Action
Jan 4.8" 0" ❄️ Dormant
Feb 4.3" 5" 0" ✅ Rainfall sufficient
Mar 4.3" 3.3" 1" 💧 Light watering
Apr 4.3" 1.7" 2.6" 🚿 Regular watering
May 4.3" 0.5" 3.8" 🚿 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" 0.3" 4" 🚿 Regular watering
Oct 4.3" 0.8" 3.5" 🚿 Regular watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 3.7" 0" ❄️ Dormant

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

Leeks Planting Timeline — Humboldt County, CA

Leeks Planting Calendar

Activity When Date Range
Start Indoors January 30 Jan 30 – Feb 13
Transplant Outdoors February 27 Feb 27 – Mar 13
Direct Sow February 6 Feb 6 – Feb 27
Harvest May 29 May 29 – Aug 14
Fall Sowing October 3 Oct 3 – Oct 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 9b

📆 Growing Season

274 days in Humboldt County

Growing Tips for Humboldt County

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 →

Frequently Asked Questions

When should I plant Leeks in Humboldt County, CA?

Humboldt County is in Zone 9b with an average last frost of February 27. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Humboldt County, CA?

Humboldt County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 27 and first fall frost is November 28.

When should I plant Leeks in Humboldt County, CA?

In Humboldt County, CA, plant Leeks after the last frost (around February 27) and before the first frost (around November 28). Best results when soil holds above 50°F.

What growing zone is Humboldt County, CA for Leeks?

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

Can Leeks grow in Humboldt County's climate?

Yes — Leeks grows well in Humboldt County's temperate climate. Humboldt County averages a 275-day frost-free season, with last frost around February 27 and first frost around November 28.

🌱

Your Humboldt County Garden Planner — Free

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

Sources & credits

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