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When to plant Crosne in Cass County, IA

Cass County gardeners should plant Crosne between April 11 and May 2 in spring. With Cass County's Zone 5b climate (last frost April 25), Crosne needs 150–200 days to mature — plant by March 23 for a full harvest. A second sowing from July 31 to August 14 extends the harvest into fall.

When to Plant Crosne in Cass County, IA

Cass County, Iowa Zone 5b June

June to-do list for Cass County, Iowa

Your garden in Cass County, Iowa is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 25
Avg. first frost October 9
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 15 hrs
Before July arrives, get these ready
  • Fall sowing: crosne

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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.

Cass County, Iowa is in USDA Zone 5b. The average last spring frost is April 25 and the first fall frost is October 9, giving you a growing season of approximately 167 days.

At an elevation of 1,043 feet, Cass County receives approximately 31.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Crosne during the growing season.

Cass County, IA (Zone 5b) Moderate season
167 days
Last Spring Frost April 25
167 growing days
First Fall Frost October 9

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Crosne Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 20 🍅 Harvest: Sep 21 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: Apr 25 🍅 Harvest: Sep 26 – Oct 10
Safe Start (90%) ✗ May not fit
Transplant: May 12 🍅 Harvest: Oct 13 – 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 Cass County

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

Soil pH

Your soil pH (6.2–6.7) is within Crosne's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — 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.

Crosne Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 324 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 1.5" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 3.4" 0.9" 💧 Light watering
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cass 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 2,421 GDD Tight fit

Crosne Planting Timeline — Cass County, IA

Crosne Planting Calendar

Activity When Date Range
Direct Sow April 11 Apr 11 – May 2
Harvest September 12 Sep 12 – Sep 26
Fall Sowing July 31 Jul 31 – Aug 14

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
November
December

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: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

167 days in Cass County

Growing Tips for Crosne in Cass County

Direct sow Crosne outdoors after April 25 in Cass County when soil has warmed and frost danger has passed.

Your 167.0-day growing season in Cass 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 Cass County, IA?

Cass County is in Zone 5b with an average last frost of April 25. Plan your Crosne planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, IA?

Cass County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 25 and first fall frost is October 9.

When should I plant Crosne in Cass County, IA?

In Cass County, IA, plant Crosne after the last frost (around April 25) and before the first frost (around October 9). Best results when soil holds above 50°F.

What growing zone is Cass County, IA for Crosne?

Cass County sits in USDA Zone 5b. Crosne grows reliably in zones 4a through 9b, so it's a good fit here.

Can Crosne grow in Cass County's climate?

Yes — Crosne grows well in Cass County's temperate climate. Cass County averages a 167-day frost-free season, with last frost around April 25 and first frost around October 9.

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Your Cass County Garden Planner — Free

A 22-page printable planner built for Cass 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 Cass County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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