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When to Plant Carrots in Webster County, IA

Webster County, Iowa Zone 5a May

What to do in May

Here's what deserves your attention in Webster County, Iowa this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost April 28
Avg. first frost October 6
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
A few tasks this May that'll pay off in June
  • First harvests: carrots

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Carrots are a popular root vegetable available in orange, purple, white, and yellow varieties. They are rich in beta-carotene and have a sweet, earthy flavor.

Webster County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 6, giving you a growing season of approximately 161 days.

At an elevation of 1,065 feet, Webster County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Carrots to ensure they mature before fall.

Webster County, IA (Zone 5a) Moderate season
161 days
Last Spring Frost April 28
161 growing days
First Fall Frost October 6

Webster County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (63 days to spare)
Transplant: Apr 22 🍅 Harvest: Jun 24 – Jul 29
Recommended (50%) ✓ Fits season (63 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 4
Safe Start (90%) ✓ Fits season (58 days to spare)
Transplant: May 14 🍅 Harvest: Jul 16 – Aug 20

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 Webster County

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

Soil pH

Your soil pH (6.2–7.3) overlaps with Carrots's range (6.0–6.8), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Carrots.

Organic Matter

Organic matter is excellent (4.4%) — Carrots will thrive.

How to Plant Carrots

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

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

Succession Planting Carrots

3
successive plantings in your 161-day season

Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.

For a dedicated fall crop, sow by Jul 28.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 361 gal / 100 sq ft

Monthly Watering Guide for Carrots

Carrots needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Carrots Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3.5" 2.6" 0.9" 💧 Light watering
May 3.5" 3.4" 0.1" 💧 Light watering
Jun 3.5" 3.6" 0" ✅ Rainfall sufficient
Jul 3.5" 3.1" 0.4" 💧 Light watering
Aug 3.5" 3" 0.5" 💧 Light watering
Sep 3.5" 3.2" 0.3" 💧 Light watering
Oct 3.5" 2.5" 1" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

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

Carrots 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.

Carrots needs ~700 GDD — county provides 1,610 GDD Excellent fit

Carrots Planting Timeline — Webster County, IA

Carrots Planting Calendar

Activity When Date Range
Direct Sow April 14 Apr 14 – May 5
Harvest June 16 Jun 16 – Jul 21
Fall Sowing July 28 Jul 28 – Aug 11

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–6.8 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

161 days in Webster County

Growing Tips for Carrots in Webster County

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

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

General growing tips

Sow seeds directly in loose, stone-free soil for straight roots. Keep soil moist until germination which can take 2-3 weeks. Thin seedlings to 2 inches apart.

Companion Planting

Good Companions

Avoid Planting Near

  • Dill
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Carrots Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Replant roots for 2nd year flowers. Harvest umbels when brown.
Storage Store airtight; viable 3 years at 35°F, under 50% humidity.

Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial — requires two seasons.

Frequently Asked Questions

When should I plant Carrots in Webster County, IA?

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

What planting zone is Webster County, IA?

Webster County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 6.

🌱

Your Webster County Garden Planner — Free

A 24-page printable planner built for Webster 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 Webster 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.