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When to Plant Leeks in Delaware County, NY

Delaware County, New York Zone 5b May

May in the garden — Delaware County, New York

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 11
Avg. first frost October 8
Soil temp (4") 56°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Move leeks from tray to bed

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

To set up a strong June, finish these tasks
  • Starting indoors: 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.

Delaware County, New York is in USDA Zone 5b. The average last spring frost is May 11 and the first fall frost is October 8, giving you a growing season of approximately 150 days.

At an elevation of 1,053 feet, Delaware County receives approximately 44.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Leeks to ensure they mature before fall.

Delaware County, NY (Zone 5b) Moderate season
150 days
Last Spring Frost May 11
150 growing days
First Fall Frost October 8

Delaware County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Aug 3 – Oct 19
Recommended (50%) ✗ May not fit
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Aug 10 – Oct 26
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: May 25 🍅 Harvest: Aug 24 – Nov 9

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 Delaware County

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

Soil pH

Your soil pH (4.9–6.5) is more acidic than Leeks prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Leeks.

Organic Matter

Organic matter is moderate (3.7%). 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
1.2″/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 3" 0" ❄️ Dormant
Feb 3.5" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.4" 0" ❄️ Dormant
May 3.5" 3.5" 0" ✅ Rainfall sufficient
Jun 3.5" 4.1" 0" ✅ Rainfall sufficient
Jul 3.5" 4" 0" ✅ Rainfall sufficient
Aug 3.5" 3.8" 0" ✅ Rainfall sufficient
Sep 3.5" 3.6" 0" ✅ Rainfall sufficient
Oct 3.5" 3.5" 0" ✅ Rainfall sufficient
Nov 3.5" 0" ❄️ Dormant
Dec 3.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Delaware 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 ~1,560 GDD — county provides 1,950 GDD Good fit

Leeks Planting Timeline — Delaware County, NY

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 11 May 11 – May 25
Direct Sow April 27 Apr 27 – May 18
Harvest August 10 Aug 10 – Oct 26
Fall Sowing July 30 Jul 30 – Aug 13

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5b

📆 Growing Season

150 days in Delaware County

Growing Tips for Leeks in Delaware County

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

Your 150.0-day growing season in Delaware 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 Delaware County, NY?

Delaware County is in Zone 5b 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 Delaware County, NY?

Delaware County, New York is in USDA Hardiness Zone 5b. The average last spring frost is May 11 and first fall frost is October 8.

🌱

Your Delaware County Garden Planner — Free

A 24-page printable planner built for Delaware County (Zone 5b). 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 Delaware County, NY. Local conditions may vary. Last updated: May 2026.

Sources & credits

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