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When to Plant Leeks in Benton County, WA

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.

Benton County, Washington is in USDA Zone 7b. The average last spring frost is April 3 and the first fall frost is October 27, giving you a growing season of approximately 207 days.

At an elevation of 2,633 feet, Benton County receives approximately 22.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Leeks during the growing season.

Benton County, WA (Zone 7b) Long season
207 days
Last Spring Frost April 3
207 growing days
First Fall Frost October 27

Benton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.3

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 3.2" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.3" 1.5" 2.8" 🚿 Regular watering
May 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 0.4" 3.9" 🚿 Regular watering
Aug 4.3" 0.4" 3.9" 🚿 Regular watering
Sep 4.3" 0.8" 3.5" 🚿 Regular watering
Oct 4.3" 2" 2.3" 🚿 Regular watering
Nov 3.7" 0" ❄️ Dormant
Dec 3.5" 0" ❄️ Dormant

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

Leeks Planting Timeline — Benton County, WA

Leeks Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow March 20 Mar 20 – Apr 10
Harvest July 3 Jul 3 – Sep 18
Fall Sowing August 18 Aug 18 – Sep 1

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May
June
July Harvest
August Fall Sowing Harvest
September Fall Sowing Harvest
October
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 7b

📆 Growing Season

207 days in Benton County

Growing Tips for Benton 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 Benton County, WA?

Benton County is in Zone 7b with an average last frost of April 3. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benton County, WA?

Benton County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 3 and first fall frost is October 27.

🌱

Your Benton County Garden Planner — Free

A 22-page printable planner built for Benton County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Benton County, WA. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.