Blog

When to Plant Leeks in Wells County, ND

Wells County, North Dakota Zone 4a May

May to-do list for Wells County, North Dakota

Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 11
Avg. first frost September 29
Soil temp (4") 52°F
Watering Low
Pest pressure Low
Daylight 14.9 hrs
  1. Harden off and plant leeks

    Frost risk is low now in Wells County, North Dakota. If you've been covering beds overnight, you can stop.

  2. Outdoor sowing time: leeks

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

Looking ahead to June
  • Starting indoors: leeks

Instant PDF download. No spam, unsubscribe any time.

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.

Wells County, North Dakota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is September 29, giving you a growing season of approximately 141 days.

At an elevation of 796 feet, Wells County receives approximately 29.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Wells County, ND (Zone 4a) Short season
141 days
Last Spring Frost May 11
141 growing days
First Fall Frost September 29
Share this guide:

Wells County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 22 Transplant: May 3 🍅 Harvest: Aug 2 – Sep 27
Recommended (50%) ✗ May not fit
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Aug 10 – Oct 5
Safe Start (90%) ✗ May not fit
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Aug 19 – Oct 14

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 Wells County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Leeks.

How to Plant Leeks

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.9″/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 0.7" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 3.5" 4.8" 0" ✅ Rainfall sufficient
Jun 3.5" 5.1" 0" ✅ Rainfall sufficient
Jul 3.5" 3.6" 0" ✅ Rainfall sufficient
Aug 3.5" 3.6" 0" ✅ Rainfall sufficient
Sep 3.5" 2.6" 0.9" 💧 Light watering
Oct 1.6" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Wells 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 ~1,200 GDD — county provides 1,410 GDD Good fit

Leeks Planting Timeline — Wells County, ND

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 4 May 4 – May 25
Harvest August 10 Aug 10 – Oct 5
Fall Sowing July 7 Jul 7 – Jul 21

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

Month-by-Month Timeline

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

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: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

141 days in Wells County

Growing Tips for Leeks in Wells County

Direct sow Leeks outdoors after May 11 in Wells County when soil has warmed and frost danger has passed.

Your 141.0-day growing season in Wells County is tight for Leeks (90.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Wells County, ND?

Wells County is in Zone 4a with an average last frost of May 11. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wells County, ND?

Wells County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is September 29.

🌱

Your Wells County Garden Planner — Free

A 24-page printable planner built for Wells County (Zone 4a). 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 Wells County, ND. 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.