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When to Plant Green Beans in Coos County, NH

Coos County, New Hampshire Zone 4b May

Your May planting checklist for Coos County, New Hampshire

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 18
Avg. first frost September 30
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
Before June arrives, get these ready
  • Direct-sowing: green beans

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Green beans are a warm-season staple available as bush or pole types. Bush beans produce a concentrated harvest while pole beans provide a longer picking season.

Coos County, New Hampshire is in USDA Zone 4b. The average last spring frost is May 18 and the first fall frost is September 30, giving you a growing season of approximately 135 days.

At an elevation of 604 feet, Coos County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Green Beans to ensure they mature before fall.

Coos County, NH (Zone 4b) Short season
135 days
Last Spring Frost May 18
135 growing days
First Fall Frost September 30
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Coos County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (20 days to spare)
Transplant: May 11 🍅 Harvest: Jul 6 – Aug 31
Recommended (50%) ✓ Fits season (23 days to spare)
Transplant: May 18 🍅 Harvest: Jul 13 – Sep 7
Safe Start (90%) ✓ Fits season (25 days to spare)
Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 22

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 Coos County

How your county's soil matches Green Beans's growing requirements.

Soil pH

Your soil pH (5.2–6.6) is more acidic than Green Beans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Green Beans.

How to Plant Green Beans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Green Beans

3
successive plantings in your 135-day season

Sow every 5.7 weeks. Last sowing by Jul 27 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Green Beans

Green Beans needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Green Beans Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 3.9" 3.6" 0.3" 💧 Light watering
Jun 3.9" 3.5" 0.4" 💧 Light watering
Jul 3.9" 3.9" 0" ✅ Rainfall sufficient
Aug 3.9" 4" 0" ✅ Rainfall sufficient
Sep 3.9" 3.7" 0.2" 💧 Light watering
Oct 3.1" 0" ❄️ Dormant
Nov 3.1" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

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

Green Beans 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.

Green Beans needs ~748 GDD — county provides 1,755 GDD Excellent fit

Green Beans Planting Timeline — Coos County, NH

Green Beans Planting Calendar

Activity When Date Range
Direct Sow June 1 Jun 1 – Jun 22
Harvest July 27 Jul 27 – Sep 21

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Direct Sow
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Natural rainfall sufficient

📅 Days to Maturity

50–65 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4b

📆 Growing Season

135 days in Coos County

Growing Tips for Green Beans in Coos County

Direct sow Green Beans outdoors after May 18 in Coos County when soil has warmed and frost danger has passed.

Common pests for Green Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost when soil is warm. Provide sturdy supports for pole varieties. Pick beans regularly when young and tender to encourage continued production.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Green Beans Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Allow pods to dry fully on vine until they rattle.
Storage Store airtight; viable 4 years at 35°F, under 45% humidity.

Avoid harvesting during damp weather. Isolate 25 ft between varieties.

Frequently Asked Questions

When should I plant Green Beans in Coos County, NH?

Coos County is in Zone 4b with an average last frost of May 18. Plan your Green Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Coos County, NH?

Coos County, New Hampshire is in USDA Hardiness Zone 4b. The average last spring frost is May 18 and first fall frost is September 30.

🌱

Your Coos County Garden Planner — Free

A 24-page printable planner built for Coos County (Zone 4b). 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 Coos County, NH. 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.