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When to Plant Arugula in Mesa County, CO

Mesa County, Colorado Zone 7a May

Top priorities for Mesa County, Colorado gardeners in May

Your Mesa County, Colorado garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 1
Avg. first frost October 9
Soil temp (4") 45°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
  1. Time to transplant arugula

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

Before June arrives, get these ready
  • Starting indoors: arugula
  • First harvests: arugula

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Arugula is a fast-growing cool-season green with a peppery, nutty flavor. It is excellent in salads and can be harvested as baby greens or mature leaves.

Mesa County, Colorado is in USDA Zone 7a. The average last spring frost is May 1 and the first fall frost is October 9, giving you a growing season of approximately 161 days.

At an elevation of 6,091 feet, Mesa County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Arugula during the growing season.

Mesa County, CO (Zone 7a) Moderate season
161 days
Last Spring Frost May 1
161 growing days
First Fall Frost October 9

Mesa County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (67 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: May 27 – Jul 29
Recommended (50%) ✓ Fits season (63 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jun 5 – Aug 7
Safe Start (90%) ✓ Fits season (66 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jun 18 – Aug 20

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 Mesa County

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

Soil pH

Your soil pH (6.7–8.1) is more alkaline than Arugula prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Mesa County is excellent for Arugula — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Arugula.

How to Plant Arugula

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Arugula

6
successive plantings in your 161-day season

Sow every 3.4 weeks. Last sowing by Aug 20 to harvest before frost.

For a dedicated fall crop, sow by Jul 31.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Arugula

Arugula needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Arugula Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 2.6" 2.6" 0" ✅ Rainfall sufficient
Jun 2.6" 1.8" 0.8" 💧 Light watering
Jul 2.6" 2.1" 0.5" 💧 Light watering
Aug 2.6" 2.5" 0.1" 💧 Light watering
Sep 2.6" 1.9" 0.7" 💧 Light watering
Oct 2.6" 1.8" 0.8" 💧 Light watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Mesa County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Arugula 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.

Arugula needs ~730 GDD — county provides 2,938 GDD Excellent fit

Arugula Planting Timeline — Mesa County, CO

Arugula Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 – Apr 10
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 17 Apr 17 – May 8
Harvest June 5 Jun 5 – Aug 7
Fall Sowing July 31 Jul 31 – Aug 14

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

161 days in Mesa County

Growing Tips for Arugula in Mesa County

Direct sow Arugula outdoors after May 01 in Mesa County when soil has warmed and frost danger has passed.

Summer highs in Mesa County reach 91°F — grow Arugula as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 161.0-day season in Mesa County allows multiple plantings of Arugula. Sow every 15.0 days for continuous harvest.

Common pests for Arugula in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly every 2-3 weeks for continuous harvest. Provide afternoon shade in warm weather to prevent bolting. Harvest outer leaves first to extend production.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Arugula in Mesa County, CO?

Mesa County is in Zone 7a with an average last frost of May 1. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mesa County, CO?

Mesa County, Colorado is in USDA Hardiness Zone 7a. The average last spring frost is May 1 and first fall frost is October 9.

🌱

Your Mesa County Garden Planner — Free

A 24-page printable planner built for Mesa County (Zone 7a). 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 Mesa 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.