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When to plant Cucumber in DeKalb County County,

DeKalb County County's spring Cucumber window runs April 29 through May 20. time plantings around the expected last-frost window for best survival.

When to Plant Cucumber in DeKalb County, IL

DeKalb County, Illinois Zone 5b June

Your June planting checklist for DeKalb County, Illinois

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 22
Avg. first frost October 16
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 15 hrs
July will be here before you know it — start on
  • First harvests: cucumber

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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.

DeKalb County, Illinois is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 16, giving you a growing season of approximately 177 days.

At an elevation of 1,332 feet, DeKalb County receives approximately 34.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Cucumber during the growing season.

DeKalb County, IL (Zone 5b) Moderate season
177 days
Last Spring Frost April 22
177 growing days
First Fall Frost October 16
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DeKalb County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Cucumber Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Mar 12 Transplant: Apr 30 🍅 Harvest: Jun 25 – Aug 20
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Mar 18 Transplant: May 6 🍅 Harvest: Jul 1 – Aug 26
Safe Start (90%) ✓ Fits season (48 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.

Soil Compatibility in DeKalb County

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

Soil pH

Your soil pH (6.2–7.2) overlaps with Cucumber's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Cucumber is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is excellent (5.1%) — 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 177-day season

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

Cucumber Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 2,148 gal / 100 sq ft
Drought risk

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

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 1.6" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 6.5" 3.1" 3.4" 🚿 Regular watering
May 6.5" 3.7" 2.8" 💧 Light watering
Jun 6.5" 4.4" 2.1" 💧 Light watering
Jul 6.5" 3.9" 2.6" 💧 Light watering
Aug 6.5" 4.1" 2.4" 💧 Light watering
Sep 6.5" 3.1" 3.4" 🚿 Regular watering
Oct 6.5" 2.6" 3.9" 🚿 Regular watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in DeKalb County). Supplement amounts are based on average rainfall — 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" — 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.

Cucumber needs ~915 GDD — county provides 2,699 GDD Excellent fit

Cucumber Planting Timeline — DeKalb County, IL

Cucumber Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest July 1 Jul 1 – Aug 26

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

177 days in DeKalb County

Growing Tips for Cucumber in DeKalb County

Direct sow Cucumber outdoors after April 22 in DeKalb 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 DeKalb County, IL?

DeKalb County is in Zone 5b with an average last frost of April 22. Plan your Cucumber planting based on this frost date — see the calendar above for exact timing.

What planting zone is DeKalb County, IL?

DeKalb County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 16.

When should I plant Cucumber in DeKalb County, ?

In DeKalb County, , plant Cucumber after the last frost (around April 22) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is DeKalb County, for Cucumber?

DeKalb County sits in USDA Zone 5b. Cucumber grows reliably in zones 3a through 11b, so it's a good fit here.

Can Cucumber grow in DeKalb County's climate?

Yes — Cucumber grows well in DeKalb County's temperate climate. DeKalb County averages a 177-day frost-free season, with last frost around April 22 and first frost around October 16.

🌱

Your DeKalb County Garden Planner — Free

A 22-page printable planner built for DeKalb 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 DeKalb 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.