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When to Plant Caraway in Linn County, IA

Linn County, Iowa Zone 5a May

May in the garden — Linn County, Iowa

Your Linn County, Iowa garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 25
Avg. first frost October 11
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Get caraway seeds going inside

    You're about 22 weeks out from your last frost — the perfect window to get these germinating indoors.

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Caraway is a biennial herb grown for its distinctive crescent-shaped seeds used in rye bread, sauerkraut, and European cuisine. The leaves and roots are also edible.

Linn County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 11, giving you a growing season of approximately 169 days.

At an elevation of 938 feet, Linn County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Caraway to ensure they mature before fall.

Linn County, IA (Zone 5a) Moderate season
169 days
Last Spring Frost April 25
169 growing days
First Fall Frost October 11

Linn County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Start indoors: Mar 14 Transplant: Apr 11
Recommended (50%) ✓ Fits season
Start indoors: Mar 21 Transplant: Apr 18
Safe Start (90%) ✓ Fits season
Start indoors: Apr 6 Transplant: May 4

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 Linn County

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

Soil pH

Your soil pH (5.7–7.2) overlaps with Caraway's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Caraway.

Organic Matter

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

How to Plant Caraway

0.5"
Planting Depth
8"
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
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 718 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Caraway

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

Month Caraway Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 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 (Apr–Oct in Linn County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Caraway 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.

Caraway needs ~4,992 GDD — county provides 2,070 GDD May not mature

Caraway Planting Timeline — Linn County, IA

Caraway Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 11 Apr 11 – May 2
Fall Sowing August 2 Aug 2 – Aug 16

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July
August Fall Sowing
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

365–450 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

169 days in Linn County

Growing Tips for Caraway in Linn County

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

Your 169.0-day growing season in Linn County is tight for Caraway (365.0-450.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Caraway in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Caraway produces seeds in its second year. Harvest seed heads when they turn brown. The young leaves can be used like parsley.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Caraway in Linn County, IA?

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

What planting zone is Linn County, IA?

Linn County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 11.

🌱

Your Linn County Garden Planner — Free

A 24-page printable planner built for Linn 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 Linn 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.