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When to Plant Leeks in Prince William County, VA

Prince William County, Virginia Zone 7a May

May in Prince William County, Virginia — your action list

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Prince William County, Virginia.

Avg. last frost April 13
Avg. first frost October 26
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 14.1 hrs
  1. Start leeks indoors

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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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.

Prince William County, Virginia is in USDA Zone 7a. The average last spring frost is April 13 and the first fall frost is October 26, giving you a growing season of approximately 196 days.

At an elevation of 372 feet, Prince William County receives approximately 46.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Leeks during the growing season.

Prince William County, VA (Zone 7a) Moderate season
196 days
Last Spring Frost April 13
196 growing days
First Fall Frost October 26

Prince William County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Feb 25 Transplant: Apr 1 🍅 Harvest: Jul 1 – Sep 16
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jul 13 – Sep 28
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Aug 7 – Oct 23

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 Prince William County

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

Soil pH

Your soil pH (5.8–7.0) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Leeks.

How to Plant Leeks

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 4.5" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 3.5" 3.5" 0" ✅ Rainfall sufficient
May 3.5" 4.1" 0" ✅ Rainfall sufficient
Jun 3.5" 4.1" 0" ✅ Rainfall sufficient
Jul 3.5" 4.6" 0" ✅ Rainfall sufficient
Aug 3.5" 4.1" 0" ✅ Rainfall sufficient
Sep 3.5" 3.1" 0.4" 💧 Light watering
Oct 3.5" 2.8" 0.7" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Prince William 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 ~2,010 GDD — county provides 3,283 GDD Excellent fit

Leeks Planting Timeline — Prince William County, VA

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow March 30 Mar 30 – Apr 20
Harvest July 13 Jul 13 – Sep 28
Fall Sowing August 17 Aug 17 – Aug 31

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

196 days in Prince William County

Growing Tips for Leeks in Prince William County

Direct sow Leeks outdoors after April 13 in Prince William 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 →

Frequently Asked Questions

When should I plant Leeks in Prince William County, VA?

Prince William County is in Zone 7a with an average last frost of April 13. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Prince William County, VA?

Prince William County, Virginia is in USDA Hardiness Zone 7a. The average last spring frost is April 13 and first fall frost is October 26.

🌱

Your Prince William County Garden Planner — Free

A 24-page printable planner built for Prince William County (Zone 7a). 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 Prince William County, VA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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