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When to plant Sweet Pea in Winneshiek County County,

Plant Sweet Pea in Winneshiek County County after May 3; the prime window is March 29–April 19.

When to Plant Sweet Pea in Winneshiek County, IA

Winneshiek County, Iowa Zone 5a June

June in the garden — Winneshiek County, Iowa

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

Avg. last frost May 3
Avg. first frost October 6
Soil temp (4") 63°F
Watering Low
Pest pressure High
Daylight 15.2 hrs
  1. Time to start sweet pea inside

    You're about 16 weeks out from your last frost — the perfect window to get these germinating indoors.

July prep starts now
  • First harvests: sweet pea

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Sweet peas (Lathyrus odoratus) are beloved cool-season climbing annuals grown primarily for their intensely fragrant, ruffled blooms in shades of pink, purple, red, and white. They thrive in cool spring conditions, climbing trellises to 4–6 feet, and make outstanding cut flowers. Bloom ceases once summer heat arrives, making early sowing critical for a long cutting season.

Winneshiek County, Iowa is in USDA Zone 5a. The average last spring frost is May 3 and the first fall frost is October 6, giving you a growing season of approximately 156 days.

At an elevation of 1,360 feet, Winneshiek County receives approximately 32.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Sweet Pea to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Good for cutting Fragrant
Winneshiek County, IA (Zone 5a) Moderate season
156 days
Last Spring Frost May 3
156 growing days
First Fall Frost October 6
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Winneshiek County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Sweet Pea Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 15 Transplant: Apr 26 🌸 Bloom: Jul 12 – Sep 13
Recommended (50%) ✓ Fits season (16 days to spare)
Start indoors: Mar 22 Transplant: May 3 🌸 Bloom: Jul 19 – Sep 20
Safe Start (90%) ✓ Fits season (13 days to spare)
Start indoors: Apr 4 Transplant: May 16 🌸 Bloom: Aug 1 – Oct 3

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 Winneshiek County

How your county's soil matches Sweet Pea's growing requirements.

Soil pH

Your soil pH (5.9–6.8) is more acidic than Sweet Pea prefers (7.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Sweet Pea will thrive.

How to Plant Sweet Pea

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

Succession Planting Sweet Pea

2
successive plantings in your 156-day season

Sow every 7.4 weeks. Last sowing by Jul 13 to harvest before frost.

Sweet Pea Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 195 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Sweet Pea

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

Month Sweet Pea Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 3.8" 0.5" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Sweet Pea 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.

Sweet Pea needs ~750 GDD — county provides 1,560 GDD Excellent fit

Sweet Pea Planting Timeline — Winneshiek County, IA

Sweet Pea Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors May 3 May 3 – May 17
Direct Sow March 29 Mar 29 – Apr 19
Bloom July 19 Jul 19 – Sep 20

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 7–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

156 days in Winneshiek County

Growing Tips for Sweet Pea in Winneshiek County

Direct sow Sweet Pea outdoors after May 03 in Winneshiek County when soil has warmed and frost danger has passed.

Common pests for Sweet Pea in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Soak seeds 24 hours before sowing to soften the hard seed coat; nick the seed coat with a file for the fastest germination. In cold zones (2–6), direct-sow as soon as soil can be worked, 4–6 weeks before last frost; seedlings tolerate light frost but not a hard freeze. In zones 7–9, fall-sow 8–10 weeks before first frost for earlier, stronger spring bloom. Provide a trellis or netting from the start. Feed with low-nitrogen, high-potassium fertilizer once buds form. Pick blooms regularly — even one mature seed pod stops flower production. All plant parts are mildly toxic if eaten.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Pea in Winneshiek County, IA?

Winneshiek County is in Zone 5a with an average last frost of May 3. Plan your Sweet Pea planting based on this frost date — see the calendar above for exact timing.

What planting zone is Winneshiek County, IA?

Winneshiek County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 6.

When should I plant Sweet Pea in Winneshiek County County, ?

In Winneshiek County County, , plant Sweet Pea after the last frost (around May 3) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Winneshiek County County, for Sweet Pea?

Winneshiek County County sits in USDA Zone 5a. Sweet Pea grows reliably in zones 2a through 9b, so it's a good fit here.

Can Sweet Pea grow in Winneshiek County County's climate?

Yes — Sweet Pea grows well in Winneshiek County County's temperate climate. Winneshiek County County averages a 156-day frost-free season, with last frost around May 3 and first frost around October 6.

🌱

Your Winneshiek County Garden Planner — Free

A 22-page printable planner built for Winneshiek 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 Winneshiek 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.