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When to plant Cucumber in Castleton,

For Cucumber in Castleton, the safe spring window opens around April 28 and closes around May 19. Last expected frost is April 21, first fall frost October 12, giving a 174-day growing season.

When to Plant Cucumber in Castleton, IL

Castleton, IL Zone 5b June

June in the garden — Castleton, IL

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

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

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

July prep starts now
  • 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.

Castleton, 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 Cucumber to ensure they mature before fall.

Castleton, IL (Zone 5b) Moderate season
174 days
Last Spring Frost April 21
174 growing days
First Fall Frost October 12

Castleton Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Cucumber Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Mar 12 Transplant: Apr 30 🍅 Harvest: Jun 25 – Aug 20
Recommended (50%) ✓ Fits season (48 days to spare)
Start indoors: Mar 17 Transplant: May 5 🍅 Harvest: Jun 30 – Aug 25
Safe Start (90%) ✓ Fits season (46 days to spare)
Start indoors: Apr 3 Transplant: May 22 🍅 Harvest: Jul 17 – Sep 11

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 Castleton

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

Soil pH

Your soil pH (6.0–6.9) is within Cucumber's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — 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 174-day season

Sow every 5.7 weeks. Last sowing by Aug 03 to harvest before frost.

Cucumber Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,063 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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 6.5" 3.5" 3" 💧 Light watering
May 6.5" 4.1" 2.4" 💧 Light watering
Jun 6.5" 4.1" 2.4" 💧 Light watering
Jul 6.5" 3.5" 3" 💧 Light watering
Aug 6.5" 3.3" 3.2" 💧 Light watering
Sep 6.5" 2.8" 3.7" 🚿 Regular watering
Oct 6.5" 2.9" 3.6" 🚿 Regular 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.

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 ~780 GDD — county provides 2,262 GDD Excellent fit

Cucumber Planting Timeline — Castleton, IL

Cucumber Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors May 5 May 5 – May 19
Direct Sow April 28 Apr 28 – May 19
Harvest June 30 Jun 30 – Aug 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

174 days in Stark County

Growing Tips for Cucumber in Castleton

Direct sow Cucumber outdoors after April 21 in Stark 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 →

When should I plant Cucumber in Castleton, ?

In Castleton, , plant Cucumber 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 Castleton, for Cucumber?

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

Can Cucumber grow in Castleton's climate?

Yes — Cucumber grows well in Castleton's temperate climate. Castleton 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.