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When to Plant Cucumber in Kendall County, IL

Cucumbers are a warm-season vine crop available in slicing and pickling varieties. They are prolific producers when given warmth, moisture, and a trellis to climb.

Kendall County, Illinois is in USDA Zone 5a. The average last spring frost is April 20 and the first fall frost is October 17, giving you a growing season of approximately 180 days.

At an elevation of 708 feet, Kendall County receives approximately 38.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Cucumber during the growing season.

Kendall County, IL (Zone 5a) Moderate season
180 days
Last Spring Frost April 20
180 growing days
First Fall Frost October 17

Kendall County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 18
Recommended (50%) ✓ Fits season (54 days to spare)
Start indoors: Mar 16 Transplant: May 4 🍅 Harvest: Jun 29 – Aug 24
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Apr 4 Transplant: May 23 🍅 Harvest: Jul 18 – Sep 12

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 975 gal / 100 sq ft
Cucumber needs ~825 GDD — county provides 2,475 GDD Excellent fit

Cucumber Planting Timeline โ€” Kendall County, IL

Cucumber Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors May 4 May 4 โ€“ May 18
Direct Sow April 27 Apr 27 โ€“ May 18
Harvest June 29 Jun 29 โ€“ Aug 24

Plant 0.5" deep ยท 24" apart ยท Rows 48" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

50โ€“70 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

180 days

Growing Tips for Kendall County

Direct sow after last frost or start indoors 3 weeks early. Provide a trellis for vining types to save space and improve air circulation. Harvest frequently to encourage production.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Sage

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Frequently Asked Questions

When should I plant Cucumber in Kendall County, IL?

Kendall County is in Zone 5a with an average last frost of April 20. Plan your Cucumber planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kendall County, IL?

Kendall County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 20 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kendall County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Kendall County, IL. Local conditions may vary. Last updated: April 2026.