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When to plant Cucumber in Adams County, IA

In Zone 5b (Adams County), direct-sow Cucumber between May 1 and May 22 for spring, after the April 24 last-frost mark.

When to Plant Cucumber in Adams County, IA

Adams County, Iowa Zone 5b July

Your July gardening checklist

Each item below is timed to Adams County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 24
Avg. first frost October 11
Soil temp (4") 76°F
Watering Moderate
Pest pressure High
Daylight 14.7 hrs
  1. Harvest cucumber as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

August 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.

Adams County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 998 feet, Adams County receives approximately 32.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Cucumber during the growing season.

Adams County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11

Adams County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.2

Drainage

Well Drained

Cucumber Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Start indoors: Mar 14 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 22
Recommended (50%) ✓ Fits season (44 days to spare)
Start indoors: Mar 20 Transplant: May 8 🍅 Harvest: Jul 3 – Aug 28
Safe Start (90%) ✓ Fits season (43 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 Adams County

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

Soil pH

Your soil pH (6.1–7.2) overlaps with Cucumber's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Adams 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 170-day season

Sow every 5.7 weeks. Last sowing by Aug 02 to harvest before frost.

Cucumber Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,284 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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 6.5" 3.1" 3.4" 🚿 Regular watering
May 6.5" 4.3" 2.2" 💧 Light watering
Jun 6.5" 3.8" 2.7" 💧 Light watering
Jul 6.5" 3.4" 3.1" 💧 Light watering
Aug 6.5" 3.2" 3.3" 🚿 Regular watering
Sep 6.5" 2.9" 3.6" 🚿 Regular watering
Oct 6.5" 2.6" 3.9" 🚿 Regular watering
Nov 2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Adams 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 ~870 GDD — county provides 2,465 GDD Excellent fit

Cucumber Planting Timeline — Adams County, IA

Cucumber Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest July 3 Jul 3 – Aug 28

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June
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

170 days in Adams County

Growing Tips for Cucumber in Adams County

Direct sow Cucumber outdoors after April 24 in Adams 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 Adams County, IA?

Adams County is in Zone 5b with an average last frost of April 24. Plan your Cucumber planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adams County, IA?

Adams County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 11.

When should I plant Cucumber in Adams County, IA?

In Adams County, IA, plant Cucumber after the last frost (around April 24) and before the first frost (around October 11). Best results when soil holds above 50°F.

What growing zone is Adams County, IA for Cucumber?

Adams 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 Adams County's climate?

Yes — Cucumber grows well in Adams County's temperate climate. Adams County averages a 170-day frost-free season, with last frost around April 24 and first frost around October 11.

🌱

Your Adams County Garden Planner — Free

A 22-page printable planner built for Adams 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 Adams County, IA. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.