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When to Plant Arugula in Washington County, UT

Washington County, Utah Zone 8b May

This month in Washington County, Utah

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

Avg. last frost April 6
Avg. first frost November 1
Soil temp (4") 62°F
Watering High
Pest pressure High
Daylight 14 hrs
  1. Time to start arugula inside

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Harvest arugula as they ripen

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

June will be here before you know it — start on
  • 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.

Washington County, Utah is in USDA Zone 8b. The average last spring frost is April 6 and the first fall frost is November 1, giving you a growing season of approximately 209 days.

At an elevation of 3,524 feet, Washington County receives approximately 12.7 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Arugula during the growing season. With low rainfall, drip irrigation is essential for growing Arugula successfully. Mulch heavily to conserve soil moisture.

Washington County, UT (Zone 8b) Long season
209 days
Last Spring Frost April 6
209 growing days
First Fall Frost November 1

Washington County Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (119 days to spare)
Start indoors: Feb 6 Transplant: Mar 13 🍅 Harvest: Apr 17 – Jun 19
Recommended (50%) ✓ Fits season (111 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: May 11 – Jul 13
Safe Start (90%) ✓ Fits season (80 days to spare)
Start indoors: Apr 22 Transplant: May 27 🍅 Harvest: Jul 1 – Sep 2

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 Washington County

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

Soil pH

Your soil pH (6.7–8.0) is more alkaline than Arugula prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Arugula.

Organic Matter

Organic matter is moderate (2.4%). 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

8
successive plantings in your 209-day season

Sow every 3.4 weeks. Last sowing by Sep 12 to harvest before frost.

For a dedicated fall crop, sow by Aug 23.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.3″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,171 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 2.6" 1.2" 1.4" 🚿 Regular watering
May 2.6" 1.4" 1.2" 💧 Light watering
Jun 2.6" 0.9" 1.7" 🚿 Regular watering
Jul 2.6" 1.2" 1.4" 🚿 Regular watering
Aug 2.6" 1.4" 1.2" 💧 Light watering
Sep 2.6" 0.9" 1.7" 🚿 Regular watering
Oct 2.6" 1.2" 1.4" 🚿 Regular watering
Nov 2.6" 1" 1.6" 🚿 Regular watering
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Washington 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 ~700 GDD — county provides 3,657 GDD Excellent fit

Arugula Planting Timeline — Washington County, UT

Arugula Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 23 Mar 23 – Apr 13
Harvest May 11 May 11 – Jul 13
Fall Sowing August 23 Aug 23 – Sep 6

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.6"/week · 1-2 times/week

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

209 days in Washington County

Growing Tips for Arugula in Washington County

Direct sow Arugula outdoors after April 06 in Washington County when soil has warmed and frost danger has passed.

Your generous 209.0-day season in Washington 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 Washington County, UT?

Washington County is in Zone 8b with an average last frost of April 6. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, UT?

Washington County, Utah is in USDA Hardiness Zone 8b. The average last spring frost is April 6 and first fall frost is November 1.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Washington County, UT. 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.