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When to Plant Crosne in Tama County, IA

Tama County, Iowa Zone 5a May

This month in Tama County, Iowa

We've pulled the most time-sensitive tasks for Tama County, Iowa this May and put them front and centre. Tackle them in order.

Avg. last frost April 28
Avg. first frost October 8
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.

Tama County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 8, giving you a growing season of approximately 163 days.

At an elevation of 1,268 feet, Tama County receives approximately 38.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Crosne during the growing season.

Tama County, IA (Zone 5a) Moderate season
163 days
Last Spring Frost April 28
163 growing days
First Fall Frost October 8

Tama County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

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: Apr 28 🍅 Harvest: Sep 29 – Oct 13
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 Tama County

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

Soil pH

Your soil pH (5.8–6.9) overlaps with Crosne's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Crosne.

Organic Matter

Organic matter is excellent (5.1%) — 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
0.4″/week
Watering frequency 1-2 times/week
Season total 527 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 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Tama 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 ~2,406 GDD — county provides 2,241 GDD Tight fit

Crosne Planting Timeline — Tama County, IA

Crosne Planting Calendar

Activity When Date Range
Direct Sow April 14 Apr 14 – May 5
Harvest September 15 Sep 15 – Sep 29
Fall Sowing July 30 Jul 30 – Aug 13

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 · 1-2 times/week

📅 Days to Maturity

150–200 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

163 days in Tama County

Growing Tips for Crosne in Tama County

Direct sow Crosne outdoors after April 28 in Tama County when soil has warmed and frost danger has passed.

Your 163.0-day growing season in Tama 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 Tama County, IA?

Tama County is in Zone 5a with an average last frost of April 28. Plan your Crosne planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tama County, IA?

Tama County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 8.

🌱

Your Tama County Garden Planner — Free

A 24-page printable planner built for Tama County (Zone 5a). 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 Tama 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.