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When to plant Leeks in Three Rivers, MA

For Three Rivers, gardeners: plant Leeks April 16 through May 7 once soil reads 50°F. A second sowing from August 8 to August 22 extends the harvest into fall.

When to Plant Leeks in Three Rivers, MA

Leeks
Hampden County, Massachusetts Zone 6a July

Hampden County, Massachusetts gardeners: here's your July plan

Each item below is timed to Hampden County, Massachusetts's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 30
Avg. first frost October 17
Soil temp (4") 81°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Basket week: leeks

    If you can't use it all right away, check the food-preservation section of your planner.

Before August arrives, get these ready
  • First harvests: leeks
  • Fall sowing: 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.

Three Rivers, Massachusetts is in USDA Zone 6a. The average last spring frost is April 30 and the first fall frost is October 17, giving you a growing season of approximately 170 days.

At an elevation of 474 feet, Hampden County receives approximately 47.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Leeks during the growing season.

Three Rivers, MA (Zone 6a) Moderate season
170 days
Last Spring Frost April 30
170 growing days
First Fall Frost October 17

Three Rivers Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.4

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jul 25 – Oct 10
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 30 – Oct 15
Safe Start (90%) ✗ May not fit
Start indoors: Apr 12 Transplant: May 17 🍅 Harvest: Aug 16 – Nov 1

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 Three Rivers

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

Soil pH

Your soil pH (5.1–6.4) is more acidic than Leeks prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

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.

Leeks 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 3.6" 0" ❄️ Dormant
Feb 3.5" 0" ❄️ Dormant
Mar 4.3" 0" ❄️ Dormant
Apr 3.5" 3.4" 0.1" 💧 Light watering
May 3.5" 4.7" 0" ✅ Rainfall sufficient
Jun 3.5" 4.6" 0" ✅ Rainfall sufficient
Jul 3.5" 4.8" 0" ✅ Rainfall sufficient
Aug 3.5" 4" 0" ✅ Rainfall sufficient
Sep 3.5" 3.4" 0.1" 💧 Light watering
Oct 3.5" 4.3" 0" ✅ Rainfall sufficient
Nov 3.8" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hampden 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 ~1,920 GDD — county provides 2,720 GDD Excellent fit

Leeks Planting Timeline — Three Rivers, MA

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest July 30 Jul 30 – Oct 15
Fall Sowing August 8 Aug 8 – Aug 22

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
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 6a

📆 Growing Season

170 days in Hampden County

Growing Tips for Leeks in Three Rivers

Direct sow Leeks outdoors after April 30 in Hampden 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 →

When should I plant Leeks in Three Rivers, MA?

In Three Rivers, MA, plant Leeks after the last frost (around April 30) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Three Rivers, MA for Leeks?

Three Rivers sits in USDA Zone 6a. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Three Rivers's climate?

Yes — Leeks grows well in Three Rivers's temperate climate. Three Rivers averages a 170-day frost-free season, with last frost around April 30 and first frost around October 17.

🌱

Your Hampden County Garden Planner — Free

A 22-page printable planner built for Hampden County (Zone 6a). 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 Hampden County, MA. Local conditions may vary. Last updated: July 2026.