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When to Plant Arugula in Sweetwater County, WY

Sweetwater County, Wyoming Zone 5a May

May to-do list for Sweetwater County, Wyoming

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 29
Avg. first frost September 20
Soil temp (4") 31°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out arugula

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Sow arugula where they'll grow

    Your soil is 31°F — warm enough for these to germinate without babying.

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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.

Sweetwater County, Wyoming is in USDA Zone 5a. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 7,922 feet, Sweetwater County receives approximately 12.9 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Arugula to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Arugula successfully. Mulch heavily to conserve soil moisture.

Sweetwater County, WY (Zone 5a) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20
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Sweetwater County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Jun 23 – Aug 25
Recommended (50%) ✓ Fits season (16 days to spare)
Start indoors: Apr 24 Transplant: May 29 🍅 Harvest: Jul 3 – Sep 4
Safe Start (90%) ✓ Fits season (19 days to spare)
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Jul 21 – 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 Sweetwater County

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

Soil pH

Your soil pH (6.2–7.7) overlaps with Arugula's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Sweetwater 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

4
successive plantings in your 114-day season

Sow every 3.4 weeks. Last sowing by Aug 01 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 371 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 0.8" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 2.6" 1.5" 1.1" 💧 Light watering
Jun 2.6" 1" 1.6" 🚿 Regular watering
Jul 2.6" 1.1" 1.5" 🚿 Regular watering
Aug 2.6" 1.3" 1.3" 🚿 Regular watering
Sep 2.6" 1" 1.6" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Sweetwater 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 ~520 GDD — county provides 1,482 GDD Excellent fit

Arugula Planting Timeline — Sweetwater County, WY

Arugula Planting Calendar

Activity When Date Range
Start Indoors April 24 Apr 24 – May 8
Transplant Outdoors May 29 May 29 – Jun 12
Direct Sow May 15 May 15 – Jun 5
Harvest July 3 Jul 3 – Sep 4
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5a

📆 Growing Season

114 days in Sweetwater County

Growing Tips for Arugula in Sweetwater County

Direct sow Arugula outdoors after May 29 in Sweetwater County when soil has warmed and frost danger has passed.

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 Sweetwater County, WY?

Sweetwater County is in Zone 5a with an average last frost of May 29. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sweetwater County, WY?

Sweetwater County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 29 and first fall frost is September 20.

🌱

Your Sweetwater County Garden Planner — Free

A 24-page printable planner built for Sweetwater County (Zone 5a). 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 Sweetwater County, WY. 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.