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When to Plant Crosne in Poweshiek County, IA

Poweshiek County, Iowa Zone 5b May

Your May game plan for Poweshiek County, Iowa

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

Avg. last frost May 2
Avg. first frost October 7
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs

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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.

Poweshiek County, Iowa is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 1,221 feet, Poweshiek County receives approximately 36 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Crosne during the growing season.

Poweshiek County, IA (Zone 5b) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7
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Poweshiek County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 22 🍅 Harvest: Sep 23 – Oct 7
Recommended (50%) ✗ May not fit
Transplant: May 2 🍅 Harvest: Oct 3 – Oct 17
Safe Start (90%) ✗ May not fit
Transplant: May 15 🍅 Harvest: Oct 16 – Oct 30

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 Poweshiek County

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

Soil pH

Your soil pH (5.9–6.8) overlaps with Crosne's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Crosne will thrive.

How to Plant Crosne

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 73 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.4" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 3.4" 0.9" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Poweshiek 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 ~2,538 GDD — county provides 2,291 GDD Tight fit

Crosne Planting Timeline — Poweshiek County, IA

Crosne Planting Calendar

Activity When Date Range
Direct Sow April 18 Apr 18 – May 9
Harvest September 19 Sep 19 – Oct 3
Fall Sowing July 29 Jul 29 – Aug 12

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

150–200 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

158 days in Poweshiek County

Growing Tips for Crosne in Poweshiek County

Direct sow Crosne outdoors after May 02 in Poweshiek County when soil has warmed and frost danger has passed.

Your 158.0-day growing season in Poweshiek 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 Poweshiek County, IA?

Poweshiek County is in Zone 5b with an average last frost of May 2. Plan your Crosne planting based on this frost date — see the calendar above for exact timing.

What planting zone is Poweshiek County, IA?

Poweshiek County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 7.

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Your Poweshiek County Garden Planner — Free

A 24-page printable planner built for Poweshiek 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 Poweshiek County, IA. 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.