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When to plant Cucumber in McHenry County, IL

The best window to plant Cucumber in McHenry County, is April 25–May 16, when soil warms to 50°F. Last frost typically hits April 18; first frost October 20.

When to Plant Cucumber in McHenry County, IL

McHenry County, Illinois Zone 5b June

This month in McHenry County, Illinois

Your garden in McHenry County, Illinois is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 18
Avg. first frost October 20
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Basket week: cucumber

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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.

McHenry County, Illinois is in USDA Zone 5b. The average last spring frost is April 18 and the first fall frost is October 20, giving you a growing season of approximately 185 days.

At an elevation of 640 feet, McHenry County receives approximately 39.4 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.

McHenry County, IL (Zone 5b) Moderate season
185 days
Last Spring Frost April 18
185 growing days
First Fall Frost October 20

McHenry County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Cucumber Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Start indoors: Mar 9 Transplant: Apr 27 🍅 Harvest: Jun 22 – Aug 17
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Mar 14 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 22
Safe Start (90%) ✓ Fits season (58 days to spare)
Start indoors: Mar 30 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 7

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 McHenry County

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

Soil pH

Your soil pH (5.9–6.7) overlaps with Cucumber's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — 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 185-day season

Sow every 5.7 weeks. Last sowing by Aug 11 to harvest before frost.

Cucumber Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,196 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 1.9" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 6.5" 4.2" 2.3" 💧 Light watering
May 6.5" 4.2" 2.3" 💧 Light watering
Jun 6.5" 4.8" 1.7" 💧 Light watering
Jul 6.5" 4.1" 2.4" 💧 Light watering
Aug 6.5" 4.5" 2" 💧 Light watering
Sep 6.5" 3.3" 3.2" 💧 Light watering
Oct 6.5" 3.4" 3.1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in McHenry 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 2,405 GDD Excellent fit

Cucumber Planting Timeline — McHenry County, IL

Cucumber Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest June 27 Jun 27 – Aug 22

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 · 2-3 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

185 days in McHenry County

Growing Tips for Cucumber in McHenry County

Direct sow Cucumber outdoors after April 18 in McHenry 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 McHenry County, IL?

McHenry County is in Zone 5b with an average last frost of April 18. Plan your Cucumber planting based on this frost date — see the calendar above for exact timing.

What planting zone is McHenry County, IL?

McHenry County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 18 and first fall frost is October 20.

When should I plant Cucumber in McHenry County, IL?

In McHenry County, IL, plant Cucumber after the last frost (around April 18) and before the first frost (around October 20). Best results when soil holds above 50°F.

What growing zone is McHenry County, IL for Cucumber?

McHenry 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 McHenry County's climate?

Yes — Cucumber grows well in McHenry County's temperate climate. McHenry County averages a 185-day frost-free season, with last frost around April 18 and first frost around October 20.

🌱

Your McHenry County Garden Planner — Free

A 22-page printable planner built for McHenry 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 McHenry 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.