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When to Plant Watercress in Harlan County, NE

Harlan County, Nebraska Zone 6a May

What to do in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Harlan County, Nebraska.

Avg. last frost April 29
Avg. first frost October 10
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
Before June arrives, get these ready
  • Starting indoors: watercress
  • First harvests: 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.

Harlan County, Nebraska is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 10, giving you a growing season of approximately 164 days.

At an elevation of 754 feet, Harlan County receives approximately 33.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Watercress to ensure they mature before fall.

Harlan County, NE (Zone 6a) Moderate season
164 days
Last Spring Frost April 29
164 growing days
First Fall Frost October 10
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Harlan 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 (88 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Jun 3 – Jul 8
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Mar 25 Transplant: Apr 29 🍅 Harvest: Jun 10 – Jul 15
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jun 24 – Jul 29

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 Harlan County

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

Soil pH

Your soil pH (6.2–7.7) overlaps with Watercress's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Watercress will thrive.

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

4
successive plantings in your 164-day season

Sow every 4.6 weeks. Last sowing by Aug 11 to harvest before frost.

For a dedicated fall crop, sow by Aug 01.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,143 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.7" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 6.5" 3.8" 2.7" 💧 Light watering
May 6.5" 5.3" 1.2" 💧 Light watering
Jun 6.5" 5.6" 0.9" 💧 Light watering
Jul 6.5" 4" 2.5" 💧 Light watering
Aug 6.5" 4.1" 2.4" 💧 Light watering
Sep 6.5" 2.7" 3.8" 🚿 Regular watering
Oct 6.5" 2" 4.5" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Harlan 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 ~650 GDD — county provides 2,132 GDD Excellent fit

Watercress Planting Timeline — Harlan County, NE

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 15 Apr 15 – May 6
Harvest June 10 Jun 10 – Jul 15
Fall Sowing August 1 Aug 1 – Aug 15

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Fall Sowing
September
October
November
December
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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 6a

📆 Growing Season

164 days in Harlan County

Growing Tips for Watercress in Harlan County

Direct sow Watercress outdoors after April 29 in Harlan County when soil has warmed and frost danger has passed.

Your generous 164.0-day season in Harlan County allows multiple plantings of Watercress. Sow every 20.0 days for continuous harvest.

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

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 Harlan County, NE?

Harlan County is in Zone 6a with an average last frost of April 29. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harlan County, NE?

Harlan County, Nebraska is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 10.

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Your Harlan County Garden Planner — Free

A 24-page printable planner built for Harlan County (Zone 6a). 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 Harlan County, NE. 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.