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When to Plant Peppers in Madison County, ID

Madison County, Idaho Zone 5a May

Top priorities for Madison County, Idaho gardeners in May

A quick May briefing for Madison County, Idaho gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 31
Avg. first frost September 11
Soil temp (4") 41°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
Coming up in June — start thinking about
  • Transplants going out: peppers
  • Direct-sowing: 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.

Madison County, Idaho is in USDA Zone 5a. The average last spring frost is May 31 and the first fall frost is September 11, giving you a growing season of approximately 103 days.

At an elevation of 6,385 feet, Madison County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Peppers during the growing season. With low rainfall, drip irrigation is essential for growing Peppers successfully. Mulch heavily to conserve soil moisture.

Madison County, ID (Zone 5a) Short season
103 days
Last Spring Frost May 31
103 growing days
First Fall Frost September 11
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Madison County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 12 Transplant: Jun 4 🍅 Harvest: Aug 6 – Oct 15
Recommended (50%) ✗ May not fit
Start indoors: Mar 22 Transplant: Jun 14 🍅 Harvest: Aug 16 – Oct 25
Safe Start (90%) ✗ May not fit
Start indoors: Apr 12 Transplant: Jul 5 🍅 Harvest: Sep 6 – Nov 15

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 Madison County

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

Soil pH

Your soil pH (6.2–7.8) overlaps with Peppers's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Peppers.

How to Plant Peppers

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

How Much Peppers to Grow

3-5 lbs
Average yield per plant
3
Plants per person
7.5 sq ft
Space per person

For a family of 4, plant approximately 12 peppers plants in about 30 sq ft. In Madison County's 103-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.8″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 358 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.8" 2.5" 2.3" 💧 Light watering
Jun 4.8" 1.2" 3.6" 🚿 Regular watering
Jul 4.8" 1.6" 3.2" 🚿 Regular watering
Aug 4.8" 2.2" 2.6" 🚿 Regular watering
Sep 4.8" 1.6" 3.2" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Madison 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 ~1,031 GDD — county provides 1,416 GDD Excellent fit

Peppers Planting Timeline — Madison County, ID

Peppers Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors June 14 Jun 14 – Jun 28
Direct Sow June 7 Jun 7 – Jun 28
Harvest August 16 Aug 16 – Oct 25

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

103 days in Madison County

Growing Tips for Peppers in Madison County

Direct sow Peppers outdoors after May 31 in Madison County when soil has warmed and frost danger has passed.

Your 103.0-day growing season in Madison County is tight for Peppers (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Madison County receives only 19" of rain annually. Peppers needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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.

Recommended Peppers Varieties for Madison County

Fast-maturing pepper varieties for shorter seasons

Ace (50d) Gypsy (58d) Early Jalapeño (60d)

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 Madison County, ID?

Madison County is in Zone 5a with an average last frost of May 31. Plan your Peppers planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, ID?

Madison County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 31 and first fall frost is September 11.

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Your Madison County Garden Planner — Free

A 24-page printable planner built for Madison 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 Madison County, ID. 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.