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When to Plant Cilantro in Fremont County, WY

Fremont County, Wyoming Zone 5a May

May in the garden — Fremont County, Wyoming

Here's what deserves your attention in Fremont County, Wyoming this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost May 15
Avg. first frost September 21
Soil temp (4") 38°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
  1. Get cilantro in the ground

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Seed cilantro outdoors

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

June will be here before you know it — start on
  • Starting indoors: cilantro
  • First harvests: cilantro

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Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

Fremont County, Wyoming is in USDA Zone 5a. The average last spring frost is May 15 and the first fall frost is September 21, giving you a growing season of approximately 129 days.

At an elevation of 6,059 feet, Fremont County receives approximately 14.8 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Cilantro to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Cilantro successfully. Mulch heavily to conserve soil moisture.

Fremont County, WY (Zone 5a) Short season
129 days
Last Spring Frost May 15
129 growing days
First Fall Frost September 21

Fremont County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Apr 6 Transplant: May 4 🍅 Harvest: Jun 15 – Aug 17
Recommended (50%) ✓ Fits season (31 days to spare)
Start indoors: Apr 10 Transplant: May 8 🍅 Harvest: Jun 19 – Aug 21
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: May 6 Transplant: Jun 3 🍅 Harvest: Jul 15 – Sep 16

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 Fremont County

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

Soil pH

Your soil pH (6.7–7.8) is more alkaline than Cilantro prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Cilantro.

Organic Matter

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

How to Plant Cilantro

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

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

Succession Planting Cilantro

3
successive plantings in your 129-day season

Sow every 4.6 weeks. Last sowing by Jul 23 to harvest before frost.

For a dedicated fall crop, sow by Jul 13.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 232 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Cilantro

Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cilantro Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 2.2" 1.8" 0.4" 💧 Light watering
Jun 2.2" 1.2" 1" 💧 Light watering
Jul 2.2" 1.2" 1" 💧 Light watering
Aug 2.2" 1.4" 0.8" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 1.2" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Cilantro 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.

Cilantro needs ~500 GDD — county provides 1,290 GDD Excellent fit

Cilantro Planting Timeline — Fremont County, WY

Cilantro Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest June 19 Jun 19 – Aug 21
Fall Sowing July 13 Jul 13 – Jul 27

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

129 days in Fremont County

Growing Tips for Cilantro in Fremont County

Direct sow Cilantro outdoors after May 15 in Fremont County when soil has warmed and frost danger has passed.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Fremont County, WY?

Fremont County is in Zone 5a with an average last frost of May 15. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fremont County, WY?

Fremont County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 15 and first fall frost is September 21.

🌱

Your Fremont County Garden Planner — Free

A 24-page printable planner built for Fremont 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 Fremont 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.