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When to Plant Angelica in Mahaska County, IA

Mahaska County, Iowa Zone 5b April

This month in Mahaska County, Iowa

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

Avg. last frost April 27
Avg. first frost October 9
Soil temp (4") 45°F
Watering Moderate
Pest pressure Low
Daylight 13.1 hrs
  1. Time to transplant angelica

    Your last frost (April 27) has passed. These warm-season crops can handle outdoor soil now.

  2. Direct-sow angelica

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

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Angelica is a dramatic biennial herb that can reach 6 feet tall with large compound leaves and globe-shaped flower clusters. All parts are edible with a sweet, celery-like flavor.

Mahaska County, Iowa is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 9, giving you a growing season of approximately 165 days.

At an elevation of 511 feet, Mahaska County receives approximately 32.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Angelica to ensure they mature before fall.

Mahaska County, IA (Zone 5b) Moderate season
165 days
Last Spring Frost April 27
165 growing days
First Fall Frost October 9
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Mahaska County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Start indoors: Mar 17 Transplant: Apr 14
Recommended (50%) ✓ Fits season
Start indoors: Mar 23 Transplant: Apr 20
Safe Start (90%) ✓ Fits season
Start indoors: Apr 9 Transplant: May 7

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 Mahaska County

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

Soil pH

Your soil pH (5.7–7.3) overlaps with Angelica's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Angelica will thrive.

How to Plant Angelica

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
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 999 gal / 100 sq ft

Monthly Watering Guide for Angelica

Angelica needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Angelica Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 6.5" 3.1" 3.4" 🚿 Regular watering
May 6.5" 3.4" 3.1" 💧 Light watering
Jun 6.5" 4.5" 2" 💧 Light watering
Jul 6.5" 3.3" 3.2" 💧 Light watering
Aug 6.5" 3.2" 3.3" 🚿 Regular watering
Sep 6.5" 3.2" 3.3" 🚿 Regular watering
Oct 6.5" 2.4" 4.1" 🚿 Regular watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Mahaska County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Angelica 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.

Angelica needs ~6,707 GDD — county provides 2,021 GDD May not mature

Angelica Planting Timeline — Mahaska County, IA

Angelica Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow April 13 Apr 13 – May 4
Fall Sowing July 31 Jul 31 – Aug 14

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 Fall Sowing
August Fall Sowing
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

165 days in Mahaska County

Growing Tips for Angelica in Mahaska County

Direct sow Angelica outdoors after April 27 in Mahaska County when soil has warmed and frost danger has passed.

Your 165.0-day growing season in Mahaska County is tight for Angelica (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Sow fresh seeds in fall for spring germination. Provide rich, moist soil and partial shade. Harvest stems in the second year before flowering for candying or flavoring.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Angelica in Mahaska County, IA?

Mahaska County is in Zone 5b with an average last frost of April 27. Plan your Angelica planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mahaska County, IA?

Mahaska County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 9.

🌱

Your Mahaska County Garden Planner — Free

A 24-page printable planner built for Mahaska 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 Mahaska County, IA. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.