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When to plant Sweet Pea in Stark County, IL

Plant Sweet Pea in Stark County after April 21; the prime window is March 17–April 7.

When to Plant Sweet Pea in Stark County, IL

Stark County, Illinois Zone 5b June

Top priorities for Stark County, Illinois gardeners in June

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

Avg. last frost April 21
Avg. first frost October 12
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 14.9 hrs

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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.

Stark County, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 12, giving you a growing season of approximately 174 days.

At an elevation of 1,071 feet, Stark County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°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
Stark County, IL (Zone 5b) Moderate season
174 days
Last Spring Frost April 21
174 growing days
First Fall Frost October 12

Stark County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Sweet Pea Planting Risk Windows

Early Start (70% safe) ✓ Fits season (35 days to spare)
Start indoors: Mar 5 Transplant: Apr 16 🌸 Bloom: Jul 2 – Sep 3
Recommended (50%) ✓ Fits season (34 days to spare)
Start indoors: Mar 10 Transplant: Apr 21 🌸 Bloom: Jul 7 – Sep 8
Safe Start (90%) ✓ Fits season (32 days to spare)
Start indoors: Mar 27 Transplant: May 8 🌸 Bloom: Jul 24 – Sep 25

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 Stark County

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

Soil pH

Your soil pH (6.0–6.9) is more acidic than Sweet Pea prefers (7.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — Sweet Pea will thrive.

How to Plant Sweet Pea

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

Succession Planting Sweet Pea

3
successive plantings in your 174-day season

Sow every 7.4 weeks. Last sowing by Jul 19 to harvest before frost.

Sweet Pea Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 289 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Stark 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 ~975 GDD — county provides 2,262 GDD Excellent fit

Sweet Pea Planting Timeline — Stark County, IL

Sweet Pea Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow March 17 Mar 17 – Apr 7
Bloom July 7 Jul 7 – Sep 8

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

Month-by-Month Timeline

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

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 5b

📆 Growing Season

174 days in Stark County

Growing Tips for Sweet Pea in Stark County

Direct sow Sweet Pea outdoors after April 21 in Stark 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 Stark County, IL?

Stark County is in Zone 5b with an average last frost of April 21. Plan your Sweet Pea planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stark County, IL?

Stark County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 12.

When should I plant Sweet Pea in Stark County, IL?

In Stark County, IL, plant Sweet Pea after the last frost (around April 21) and before the first frost (around October 12). Best results when soil holds above 50°F.

What growing zone is Stark County, IL for Sweet Pea?

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

Can Sweet Pea grow in Stark County's climate?

Yes — Sweet Pea grows well in Stark County's temperate climate. Stark County averages a 174-day frost-free season, with last frost around April 21 and first frost around October 12.

🌱

Your Stark County Garden Planner — Free

A 22-page printable planner built for Stark 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 Stark County, IL. 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.