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When to Plant Cucumber in Fulton 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.

Fulton County, Illinois is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 16, giving you a growing season of approximately 179 days.

At an elevation of 1,162 feet, Fulton County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Cucumber to ensure they mature before fall.

Fulton County, IL (Zone 5b) Moderate season
179 days
Last Spring Frost April 20
179 growing days
First Fall Frost October 16

Fulton County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 18
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Mar 16 Transplant: May 4 🍅 Harvest: Jun 29 – Aug 24
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Jul 11 – Sep 5

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 Fulton County

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

Soil pH

Your soil pH (6.1โ€“6.7) is within Cucumber's preferred range (6.0โ€“7.0).

Soil Texture

The silt loam soil in Fulton County is excellent for Cucumber โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.0%) โ€” Cucumber will thrive.

How to Plant Cucumber

0.5"
Planting Depth
24"
Between Plants
48"
Between Rows

Succession Planting Cucumber

4
successive plantings in your 179-day season

Sow every 5.7 weeks. Last sowing by Aug 07 to harvest before frost.

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 913 gal / 100 sq ft

Monthly Watering Guide for Cucumber

Cucumber needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Cucumber Needs Rainfall You Supplement Action
Jan โ€” 1.8" 0" โ„๏ธ Dormant
Feb โ€” 1.8" 0" โ„๏ธ Dormant
Mar โ€” 2.5" 0" โ„๏ธ Dormant
Apr 6.5" 3.7" 2.8" ๐Ÿ’ง Light watering
May 6.5" 4.5" 2" ๐Ÿ’ง Light watering
Jun 6.5" 5.5" 1" ๐Ÿ’ง Light watering
Jul 6.5" 4.3" 2.2" ๐Ÿ’ง Light watering
Aug 6.5" 3.6" 2.9" ๐Ÿ’ง Light watering
Sep 6.5" 3.3" 3.2" ๐Ÿ’ง Light watering
Oct 6.5" 3.6" 2.9" ๐Ÿ’ง Light watering
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 2.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Fulton County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Cucumber 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" โ€” every day above 50ยฐF 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.

Cucumber needs ~735 GDD — county provides 2,192 GDD Excellent fit

Cucumber Planting Timeline โ€” Fulton 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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

179 days in Fulton County

Growing Tips for Cucumber in Fulton County

Direct sow Cucumber outdoors after April 20 in Fulton County when soil has warmed and frost danger has passed.

Common pests for Cucumber in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cucumber in Fulton County, IL?

Fulton County is in Zone 5b 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 Fulton County, IL?

Fulton County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 16.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Fulton County, IL. Local conditions may vary. Last updated: April 2026.