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When to Plant Microgreens in Sweetwater County, WY

Sweetwater County, Wyoming Zone 5a May

Your May planting checklist 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. Move microgreens from tray to bed

    Frost risk is low now in Sweetwater County, Wyoming. If you've been covering beds overnight, you can stop.

  2. Plant microgreens from seed, right in the garden

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Coming up in June — start thinking about
  • First harvests: microgreens

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

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 Microgreens to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Microgreens 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 (82 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: May 26 – Jun 23
Recommended (50%) ✓ Fits season (79 days to spare)
Start indoors: Apr 24 Transplant: May 29 🍅 Harvest: Jun 5 – Jul 3
Safe Start (90%) ✓ Fits season (82 days to spare)
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Jun 23 – Jul 21

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 Microgreens's growing requirements.

Soil pH

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

Soil Texture

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

Drainage

Drainage is adequate for Microgreens.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Microgreens.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Microgreens

22
successive plantings in your 114-day season

Sow every 0.7 weeks. Last sowing by Aug 30 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,004 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Microgreens

Microgreens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Microgreens 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 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1.1" 3.2" 🚿 Regular watering
Aug 4.3" 1.3" 3" 🚿 Regular watering
Sep 4.3" 1" 3.3" 🚿 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.

Microgreens 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.

Microgreens needs ~182 GDD — county provides 1,482 GDD Excellent fit

Microgreens Planting Timeline — Sweetwater County, WY

Microgreens 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 June 5 Jun 5 – Jul 3
Fall Sowing July 12 Jul 12 – Jul 26

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

114 days in Sweetwater County

Growing Tips for Microgreens in Sweetwater County

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

Your generous 114.0-day season in Sweetwater County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

Sweetwater County receives only 13" of rain annually. Microgreens needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Sweetwater County, WY?

Sweetwater County is in Zone 5a with an average last frost of May 29. Plan your Microgreens 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.

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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.