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When to Plant Leeks in Berkshire County, MA

Berkshire County, Massachusetts Zone 5b May

May to-do list for Berkshire County, Massachusetts

Your Berkshire County, Massachusetts garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 6
Avg. first frost October 12
Soil temp (4") 58°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Move leeks into the garden

    Your last frost (May 6) has passed. These warm-season crops can handle outdoor soil now.

June prep starts now
  • 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.

Berkshire County, Massachusetts is in USDA Zone 5b. The average last spring frost is May 6 and the first fall frost is October 12, giving you a growing season of approximately 159 days.

At an elevation of 392 feet, Berkshire County receives approximately 41.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Leeks during the growing season.

Berkshire County, MA (Zone 5b) Moderate season
159 days
Last Spring Frost May 6
159 growing days
First Fall Frost October 12
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Berkshire County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 25 Transplant: Apr 29 🍅 Harvest: Jul 29 – Oct 14
Recommended (50%) ✗ May not fit
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Aug 5 – Oct 21
Safe Start (90%) ✗ May not fit
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Aug 17 – Nov 2

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 Berkshire County

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

Soil pH

Your soil pH (5.1–6.7) is more acidic than Leeks prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). 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
1.1″/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 3.1" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 3.6" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 3.5" 3.7" 0" ✅ Rainfall sufficient
Jun 3.5" 4" 0" ✅ Rainfall sufficient
Jul 3.5" 3.5" 0" ✅ Rainfall sufficient
Aug 3.5" 3.6" 0" ✅ Rainfall sufficient
Sep 3.5" 3.8" 0" ✅ Rainfall sufficient
Oct 3.5" 3.2" 0.3" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Berkshire 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 ~1,740 GDD — county provides 2,305 GDD Excellent fit

Leeks Planting Timeline — Berkshire County, MA

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 22 Apr 22 – May 13
Harvest August 5 Aug 5 – Oct 21
Fall Sowing August 3 Aug 3 – Aug 17

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
August Fall Sowing Harvest
September Harvest
October Harvest
November
December
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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

159 days in Berkshire County

Growing Tips for Leeks in Berkshire County

Direct sow Leeks outdoors after May 06 in Berkshire County when soil has warmed and frost danger has passed.

Your 159.0-day growing season in Berkshire 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 Berkshire County, MA?

Berkshire County is in Zone 5b with an average last frost of May 6. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Berkshire County, MA?

Berkshire County, Massachusetts is in USDA Hardiness Zone 5b. The average last spring frost is May 6 and first fall frost is October 12.

🌱

Your Berkshire County Garden Planner — Free

A 24-page printable planner built for Berkshire 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 Berkshire County, MA. 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.