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When to Plant Mustard Greens in Laramie County, WY

Laramie County, Wyoming Zone 5b May

What to do in May

Welcome to May in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 19
Avg. first frost September 24
Soil temp (4") 39°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
  1. Set out mustard greens seedlings

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Sow mustard greens where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

June prep starts now
  • Starting indoors: mustard greens
  • First harvests: mustard greens

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Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.

Laramie County, Wyoming is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is September 24, giving you a growing season of approximately 128 days.

At an elevation of 6,153 feet, Laramie County receives approximately 19.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Mustard Greens to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Mustard Greens successfully. Mulch heavily to conserve soil moisture.

Laramie County, WY (Zone 5b) Short season
128 days
Last Spring Frost May 19
128 growing days
First Fall Frost September 24

Laramie County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Apr 7 Transplant: May 12 🍅 Harvest: Jun 16 – Aug 18
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Jun 23 – Aug 25
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: May 3 Transplant: Jun 7 🍅 Harvest: Jul 12 – Sep 13

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 Laramie County

How your county's soil matches Mustard Greens's growing requirements.

Soil pH

Your soil pH (6.5–8.2) is more alkaline than Mustard Greens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Laramie County is excellent for Mustard Greens — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Mustard Greens.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Mustard Greens.

How to Plant Mustard Greens

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 Mustard Greens

5
successive plantings in your 128-day season

Sow every 3.4 weeks. Last sowing by Aug 05 to harvest before frost.

For a dedicated fall crop, sow by Jul 16.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 378 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Mustard Greens

Mustard Greens needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Mustard Greens Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 3" 2.1" 0.9" 💧 Light watering
Jun 3" 1.3" 1.7" 🚿 Regular watering
Jul 3" 1.8" 1.2" 💧 Light watering
Aug 3" 2" 1" 💧 Light watering
Sep 3" 1.6" 1.4" 💧 Light watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Mustard Greens 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.

Mustard Greens needs ~490 GDD — county provides 1,568 GDD Excellent fit

Mustard Greens Planting Timeline — Laramie County, WY

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 – Apr 28
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 5 May 5 – May 26
Harvest June 23 Jun 23 – Aug 25
Fall Sowing July 16 Jul 16 – Jul 30

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

128 days in Laramie County

Growing Tips for Mustard Greens in Laramie County

Direct sow Mustard Greens outdoors after May 19 in Laramie County when soil has warmed and frost danger has passed.

Your generous 128.0-day season in Laramie County allows multiple plantings of Mustard Greens. Sow every 15.0 days for continuous harvest.

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

General growing tips

Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mustard Greens in Laramie County, WY?

Laramie County is in Zone 5b with an average last frost of May 19. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Laramie County, WY?

Laramie County, Wyoming is in USDA Hardiness Zone 5b. The average last spring frost is May 19 and first fall frost is September 24.

🌱

Your Laramie County Garden Planner — Free

A 24-page printable planner built for Laramie 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 Laramie 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.