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When to plant Peppers in Clayton County County,

The best window to plant Peppers in Clayton County County, is May 7–May 28, when soil warms to 50°F. Last frost typically hits April 30; first frost October 7.

When to Plant Peppers in Clayton County, IA

Peppers
Clayton County, Iowa Zone 5a June

What to do in June

Each item below is timed to Clayton County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 65°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
Before July arrives, get these ready
  • Starting indoors: peppers
  • First harvests: peppers

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Sweet peppers are warm-season crops producing fruits in a rainbow of colors. They turn from green to red, yellow, or orange as they ripen, increasing in sweetness.

Clayton County, Iowa is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 1,343 feet, Clayton County receives approximately 32.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Peppers to ensure they mature before fall.

Clayton County, IA (Zone 5a) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7
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Clayton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Peppers Planting Risk Windows

Early Start (70% safe) ✓ Fits season (12 days to spare)
Start indoors: Feb 13 Transplant: May 8 🍅 Harvest: Jul 10 – Sep 18
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Feb 19 Transplant: May 14 🍅 Harvest: Jul 16 – Sep 24
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Mar 7 Transplant: May 30 🍅 Harvest: Aug 1 – Oct 10

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 Clayton County

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

Soil pH

Your soil pH (5.9–7.3) overlaps with Peppers's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (4.0%). Annual compost additions will help Peppers.

How to Plant Peppers

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Peppers

3
successive plantings in your 160-day season

Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.

Peppers Water Budget

Plant needs
1.1″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 340 gal / 100 sq ft

Monthly Watering Guide for Peppers

Peppers needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Peppers Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.8" 3" 1.8" 💧 Light watering
May 4.8" 3.2" 1.6" 💧 Light watering
Jun 4.8" 4.3" 0.5" 💧 Light watering
Jul 4.8" 4.1" 0.7" 💧 Light watering
Aug 4.8" 3.4" 1.4" 💧 Light watering
Sep 4.8" 2.8" 2" 💧 Light watering
Oct 4.8" 2.6" 2.2" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Peppers 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.

Peppers needs ~806 GDD — county provides 1,720 GDD Excellent fit

Peppers Planting Timeline — Clayton County, IA

Peppers Planting Calendar

Activity When Date Range
Start Indoors February 19 Feb 19 – Mar 5
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 16 Jul 16 – Sep 24

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

160 days in Clayton County

Growing Tips for Peppers in Clayton County

Direct sow Peppers outdoors after April 30 in Clayton County when soil has warmed and frost danger has passed.

Common pests for Peppers in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 8-10 weeks before last frost. Transplant when nighttime temperatures stay above 55F. Avoid high-nitrogen fertilizers which promote leaves over fruit.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Kohlrabi

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Peppers Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Remove seeds from fully ripe (red/orange) fruit.
Storage Store airtight; viable 4 years at 35°F, under 50% humidity.

Isolate 300 ft for purity. Hot and sweet peppers can cross-pollinate.

Frequently Asked Questions

When should I plant Peppers in Clayton County, IA?

Clayton County is in Zone 5a with an average last frost of April 30. Plan your Peppers planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clayton County, IA?

Clayton County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 7.

When should I plant Peppers in Clayton County County, ?

In Clayton County County, , plant Peppers after the last frost (around April 30) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Clayton County County, for Peppers?

Clayton County County sits in USDA Zone 5a. Peppers grows reliably in zones 3a through 11b, so it's a good fit here.

Can Peppers grow in Clayton County County's climate?

Yes — Peppers grows well in Clayton County County's temperate climate. Clayton County County averages a 160-day frost-free season, with last frost around April 30 and first frost around October 7.

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Your Clayton County Garden Planner — Free

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

Sources & credits

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