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When to Plant Watercress in Converse County, WY

Converse County, Wyoming Zone 5a May

May to-do list for Converse County, Wyoming

May is a pivotal month for Converse County, Wyoming gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 4
Avg. first frost September 18
Soil temp (4") 37°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
  1. Put watercress seeds straight in the ground

    Your soil is 37°F — warm enough for these to germinate without babying.

June will be here before you know it — start on
  • Transplants going out: watercress

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Watercress is a semi-aquatic plant with a peppery, tangy flavor rich in vitamins and minerals. It grows naturally along streams and can be cultivated in containers with standing water.

Converse County, Wyoming is in USDA Zone 5a. The average last spring frost is June 4 and the first fall frost is September 18, giving you a growing season of approximately 106 days.

At an elevation of 6,089 feet, Converse County receives approximately 16.3 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Watercress to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Watercress successfully. Mulch heavily to conserve soil moisture.

Converse County, WY (Zone 5a) Short season
106 days
Last Spring Frost June 4
106 growing days
First Fall Frost September 18

Converse County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (35 days to spare)
Start indoors: Apr 16 Transplant: May 21 🍅 Harvest: Jul 2 – Aug 6
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Apr 30 Transplant: Jun 4 🍅 Harvest: Jul 16 – Aug 20
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: May 13 Transplant: Jun 17 🍅 Harvest: Jul 29 – 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 Converse County

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

Soil pH

Your soil pH (6.6–8.3) overlaps with Watercress's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Watercress.

How to Plant Watercress

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 Watercress

3
successive plantings in your 106-day season

Sow every 4.6 weeks. Last sowing by Jul 20 to harvest before frost.

For a dedicated fall crop, sow by Jul 10.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.7″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 967 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Watercress

Watercress needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watercress Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2" 0" ❄️ Dormant
Jun 6.5" 1.2" 5.3" 🚿 Regular watering
Jul 6.5" 1.5" 5" 🚿 Regular watering
Aug 6.5" 1.5" 5" 🚿 Regular watering
Sep 6.5" 1.3" 5.2" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Watercress 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.

Watercress needs ~538 GDD — county provides 1,139 GDD Excellent fit

Watercress Planting Timeline — Converse County, WY

Watercress Planting Calendar

Activity When Date Range
Start Indoors April 30 Apr 30 – May 14
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 21 May 21 – Jun 11
Harvest July 16 Jul 16 – Aug 20
Fall Sowing July 10 Jul 10 – Jul 24

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

106 days in Converse County

Growing Tips for Watercress in Converse County

Direct sow Watercress outdoors after June 04 in Converse County when soil has warmed and frost danger has passed.

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

Converse County receives only 16" of rain annually. Watercress needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Grow in containers with trays of water kept fresh. Provide partial shade and cool conditions. Harvest stems by cutting above water level. Replace water frequently to prevent stagnation.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watercress in Converse County, WY?

Converse County is in Zone 5a with an average last frost of June 4. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Converse County, WY?

Converse County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is June 4 and first fall frost is September 18.

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Your Converse County Garden Planner — Free

A 24-page printable planner built for Converse 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 Converse 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.