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When to Plant Garlic Chives in Hillsborough County, NH

Hillsborough County, New Hampshire Zone 6a May

Your May planting checklist for Hillsborough County, New Hampshire

Welcome to May in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 2
Avg. first frost October 11
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Transplant garlic chives outside

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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Garlic chives are a perennial herb with flat leaves that have a mild garlic flavor. They produce attractive white flower clusters and are used in Asian cooking.

Hillsborough County, New Hampshire is in USDA Zone 6a. The average last spring frost is May 2 and the first fall frost is October 11, giving you a growing season of approximately 162 days.

At an elevation of 145 feet, Hillsborough County receives approximately 44 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Garlic Chives to ensure they mature before fall.

Hillsborough County, NH (Zone 6a) Moderate season
162 days
Last Spring Frost May 2
162 growing days
First Fall Frost October 11

Hillsborough County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Transplant: May 4 🍅 Harvest: Jul 6 – Sep 14
Recommended (50%) ✓ Fits season (22 days to spare)
Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19
Safe Start (90%) ✓ Fits season (21 days to spare)
Transplant: May 24 🍅 Harvest: Jul 26 – Oct 4

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 Hillsborough County

How your county's soil matches Garlic Chives's growing requirements.

Soil pH

Your soil pH (4.9–6.6) is more acidic than Garlic Chives prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Garlic Chives prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Garlic Chives.

How to Plant Garlic Chives

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Garlic Chives

3
successive plantings in your 162-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Garlic Chives

Garlic Chives needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Garlic Chives Needs Rainfall You Supplement Action
Jan 3" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.4" 0" ❄️ Dormant
May 2.2" 4.2" 0" ✅ Rainfall sufficient
Jun 2.2" 3.7" 0" ✅ Rainfall sufficient
Jul 2.2" 4.6" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 4.2" 0" ✅ Rainfall sufficient
Oct 2.2" 3.8" 0" ✅ Rainfall sufficient
Nov 3.2" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Hillsborough County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Garlic Chives 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.

Garlic Chives needs ~975 GDD — county provides 2,106 GDD Excellent fit

Garlic Chives Planting Timeline — Hillsborough County, NH

Garlic Chives Planting Calendar

Activity When Date Range
Transplant Outdoors May 9 May 9 – May 23
Harvest July 11 Jul 11 – Sep 19

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6a

📆 Growing Season

162 days in Hillsborough County

Growing Tips for Garlic Chives in Hillsborough County

Direct sow Garlic Chives outdoors after May 02 in Hillsborough County when soil has warmed and frost danger has passed.

Common pests for Garlic Chives in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Start from seed or divisions. Cut flower stalks before seeds set to prevent aggressive self-seeding. Both leaves and flower buds are edible and flavorful.

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 Garlic Chives in Hillsborough County, NH?

Hillsborough County is in Zone 6a with an average last frost of May 2. Plan your Garlic Chives planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hillsborough County, NH?

Hillsborough County, New Hampshire is in USDA Hardiness Zone 6a. The average last spring frost is May 2 and first fall frost is October 11.

🌱

Your Hillsborough County Garden Planner — Free

A 24-page printable planner built for Hillsborough 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 Hillsborough County, NH. Local conditions may vary. Last updated: May 2026.

Sources & credits

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