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When to Plant Crosne in Coos County, NH

Coos County, New Hampshire Zone 4b May

Your May planting checklist for Coos County, New Hampshire

Your garden in Coos County, New Hampshire is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 18
Avg. first frost September 30
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
  1. Seed crosne outdoors

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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Crosne (Chinese artichoke) produces small, segmented white tubers with a crunchy texture and mild artichoke-nutty flavor. They are a rare delicacy in French cuisine.

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 Crosne 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) ✗ May not fit
Transplant: May 11 🍅 Harvest: Oct 12 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: May 18 🍅 Harvest: Oct 19 – Oct 12
Safe Start (90%) ✗ May not fit
Transplant: Jun 2 🍅 Harvest: Nov 3 – Oct 27

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 Crosne's growing requirements.

Soil pH

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

Soil Texture

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

Organic Matter

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

How to Plant Crosne

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

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

Monthly Watering Guide for Crosne

Crosne needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Crosne 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 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 3.5" 0.8" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 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.

Crosne 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.

Crosne needs ~2,275 GDD — county provides 1,755 GDD May not mature

Crosne Planting Timeline — Coos County, NH

Crosne Planting Calendar

Activity When Date Range
Direct Sow May 11 May 11 – Jun 1
Harvest October 12 Oct 12 – Oct 5
Fall Sowing July 8 Jul 8 – Jul 22

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

150–200 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4b

📆 Growing Season

135 days in Coos County

Growing Tips for Crosne in Coos County

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

Your 135.0-day growing season in Coos County is tight for Crosne (150.0-200.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant tubers 3 inches deep in spring. Mark the location well as plants die back. Harvest in late fall after frost. Leave some tubers in ground for next year. Very labor-intensive to harvest.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Crosne in Coos County, NH?

Coos County is in Zone 4b with an average last frost of May 18. Plan your Crosne 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.

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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.