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When to Plant Cucumber in Phillips County, CO

Phillips County, Colorado Zone 5b May

Your May game plan for Phillips County, Colorado

Your garden in Phillips County, Colorado is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 4
Avg. first frost October 7
Soil temp (4") 45°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Move cucumber into the garden

    Your last frost (May 4) has passed. These warm-season crops can handle outdoor soil now.

  2. Scatter cucumber into prepared beds

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

Get ahead of June
  • Starting indoors: 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.

Phillips County, Colorado is in USDA Zone 5b. The average last spring frost is May 4 and the first fall frost is October 7, giving you a growing season of approximately 156 days.

At an elevation of 5,494 feet, Phillips County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Cucumber during the growing season.

Phillips County, CO (Zone 5b) Moderate season
156 days
Last Spring Frost May 4
156 growing days
First Fall Frost October 7

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Mar 26 Transplant: May 14 🍅 Harvest: Jul 9 – Sep 3
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Mar 30 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 7
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Apr 14 Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 22

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 Phillips County

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

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Cucumber prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Phillips 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 moderate (2.4%). 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 156-day season

Sow every 5.7 weeks. Last sowing by Jul 29 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.7″/week
Watering frequency 2-3 times/week
Season total 2,302 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 6.5" 2.8" 3.7" 🚿 Regular watering
Jun 6.5" 1.5" 5" 🚿 Regular watering
Jul 6.5" 1.6" 4.9" 🚿 Regular watering
Aug 6.5" 2.5" 4" 🚿 Regular watering
Sep 6.5" 1.7" 4.8" 🚿 Regular watering
Oct 6.5" 1.8" 4.7" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Phillips 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 2,379 GDD Excellent fit

Cucumber Planting Timeline — Phillips County, CO

Cucumber Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 11 May 11 – Jun 1
Harvest July 13 Jul 13 – Sep 7

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 Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
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: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

156 days in Phillips County

Growing Tips for Cucumber in Phillips County

Direct sow Cucumber outdoors after May 04 in Phillips 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.

Phillips County receives only 21" of rain annually. Cucumber needs consistent moisture — 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 Phillips County, CO?

Phillips County is in Zone 5b with an average last frost of May 4. Plan your Cucumber planting based on this frost date — see the calendar above for exact timing.

What planting zone is Phillips County, CO?

Phillips County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 4 and first fall frost is October 7.

🌱

Your Phillips County Garden Planner — Free

A 24-page printable planner built for Phillips 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 Phillips County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

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