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When to Plant Leeks in Franklin County, NY

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.

Franklin County, New York is in USDA Zone 4a. The average last spring frost is May 18 and the first fall frost is September 27, giving you a growing season of approximately 132 days.

At an elevation of 739 feet, Franklin County receives approximately 47.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Leeks to ensure they mature before fall.

Franklin County, NY (Zone 4a) Short season
132 days
Last Spring Frost May 18
132 growing days
First Fall Frost September 27

Franklin County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Aug 10 – Oct 5
Recommended (50%) ✗ May not fit
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Aug 17 – Oct 12
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 26

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 Franklin County

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

Soil pH

Your soil pH (4.8โ€“6.5) is more acidic than Leeks prefers (6.0โ€“7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Franklin County is excellent for Leeks โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). 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
1.5″/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 โ€” 2.9" 0" โ„๏ธ Dormant
Feb โ€” 3.2" 0" โ„๏ธ Dormant
Mar โ€” 4.4" 0" โ„๏ธ Dormant
Apr โ€” 4" 0" โ„๏ธ Dormant
May 3.5" 4.5" 0" โœ… Rainfall sufficient
Jun 3.5" 4.7" 0" โœ… Rainfall sufficient
Jul 3.5" 5" 0" โœ… Rainfall sufficient
Aug 3.5" 4.2" 0" โœ… Rainfall sufficient
Sep 3.5" 3.5" 0" โœ… Rainfall sufficient
Oct โ€” 3.5" 0" โ„๏ธ Dormant
Nov โ€” 3.8" 0" โ„๏ธ Dormant
Dec โ€” 3.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Franklin County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,380 GDD — county provides 1,518 GDD Good fit

Leeks Planting Timeline โ€” Franklin County, NY

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 โ€“ Apr 20
Transplant Outdoors May 18 May 18 โ€“ Jun 1
Direct Sow May 11 May 11 โ€“ Jun 1
Harvest August 17 Aug 17 โ€“ Oct 12
Fall Sowing July 5 Jul 5 โ€“ Jul 19

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“150 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

132 days in Franklin County

Growing Tips for Leeks in Franklin County

Direct sow Leeks outdoors after May 18 in Franklin County when soil has warmed and frost danger has passed.

Your 132.0-day growing season in Franklin 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 Franklin County, NY?

Franklin County is in Zone 4a with an average last frost of May 18. Plan your Leeks planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Franklin County, NY?

Franklin County, New York is in USDA Hardiness Zone 4a. The average last spring frost is May 18 and first fall frost is September 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Franklin County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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