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When to Plant Cucumber in Jerome County, ID

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.

Jerome County, Idaho is in USDA Zone 6a. The average last spring frost is May 10 and the first fall frost is October 4, giving you a growing season of approximately 147 days.

At an elevation of 6,306 feet, Jerome County receives approximately 13.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Cucumber during the growing season. With low rainfall, drip irrigation is essential for growing Cucumber successfully. Mulch heavily to conserve soil moisture.

Jerome County, ID (Zone 6a) Short season
147 days
Last Spring Frost May 10
147 growing days
First Fall Frost October 4

Jerome County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 27 Transplant: May 15 🍅 Harvest: Jul 10 – Sep 4
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Jul 19 – Sep 13
Safe Start (90%) ✓ Fits season (14 days to spare)
Start indoors: Apr 30 Transplant: Jun 18 🍅 Harvest: Aug 13 – Oct 8

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 Jerome County

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

Soil pH

Your soil pH (6.8โ€“7.9) is more alkaline than Cucumber prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Cucumber.

How to Plant Cucumber

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

Succession Planting Cucumber

3
successive plantings in your 147-day season

Sow every 5.7 weeks. Last sowing by Jul 26 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.4″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 1,749 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1" 0" โ„๏ธ Dormant
Feb โ€” 0.8" 0" โ„๏ธ Dormant
Mar โ€” 1.3" 0" โ„๏ธ Dormant
Apr โ€” 1.6" 0" โ„๏ธ Dormant
May 6.5" 1.5" 5" ๐Ÿšฟ Regular watering
Jun 6.5" 1" 5.5" ๐Ÿšฟ Regular watering
Jul 6.5" 1.2" 5.3" ๐Ÿšฟ Regular watering
Aug 6.5" 1.3" 5.2" ๐Ÿšฟ Regular watering
Sep 6.5" 1.1" 5.4" ๐Ÿšฟ Regular watering
Oct 6.5" 1.1" 5.4" ๐Ÿšฟ Regular watering
Nov โ€” 0.8" 0" โ„๏ธ Dormant
Dec โ€” 0.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Jerome 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 ~825 GDD — county provides 2,021 GDD Excellent fit

Cucumber Planting Timeline โ€” Jerome County, ID

Cucumber Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 โ€“ Apr 19
Transplant Outdoors May 24 May 24 โ€“ Jun 7
Direct Sow May 17 May 17 โ€“ Jun 7
Harvest July 19 Jul 19 โ€“ Sep 13

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

147 days in Jerome County

Growing Tips for Cucumber in Jerome County

Direct sow Cucumber outdoors after May 10 in Jerome 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.

Jerome County receives only 14" of rain annually. Cucumber needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

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 Jerome County, ID?

Jerome County is in Zone 6a with an average last frost of May 10. Plan your Cucumber planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jerome County, ID?

Jerome County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 10 and first fall frost is October 4.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jerome County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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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 Jerome County, ID. Local conditions may vary. Last updated: April 2026.