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When to Plant Watercress in Ransom County, ND

Ransom County, North Dakota Zone 4a May

Your May game plan for Ransom County, North Dakota

Here's what deserves your attention in Ransom County, North Dakota this month. Everything below is tailored to Zone 4a and timed around your local frost dates.

Avg. last frost May 8
Avg. first frost October 3
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Time to transplant watercress

    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. Outdoor sowing time: watercress

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

Looking ahead to June
  • 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.

Ransom County, North Dakota is in USDA Zone 4a. The average last spring frost is May 8 and the first fall frost is October 3, giving you a growing season of approximately 148 days.

At an elevation of 517 feet, Ransom County receives approximately 32.4 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Watercress to ensure they mature before fall.

Ransom County, ND (Zone 4a) Short season
148 days
Last Spring Frost May 8
148 growing days
First Fall Frost October 3

Ransom County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🍅 Harvest: Jun 9 – Jul 14
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Mar 27 Transplant: May 8 🍅 Harvest: Jun 19 – Jul 24
Safe Start (90%) ✓ Fits season (72 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jun 29 – Aug 3

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 Ransom County

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

Soil pH

Your soil pH (6.7–7.3) is within Watercress's preferred range (6.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Watercress.

How to Plant Watercress

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Watercress

4
successive plantings in your 148-day season

Sow every 4.6 weeks. Last sowing by Aug 04 to harvest before frost.

For a dedicated fall crop, sow by Jul 11.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 765 gal / 100 sq ft

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 0.9" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 6.5" 5.3" 1.2" 💧 Light watering
Jun 6.5" 4.5" 2" 💧 Light watering
Jul 6.5" 4.3" 2.2" 💧 Light watering
Aug 6.5" 4.2" 2.3" 💧 Light watering
Sep 6.5" 2.8" 3.7" 🚿 Regular watering
Oct 6.5" 1.7" 4.8" 🚿 Regular watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Ransom 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 ~612 GDD — county provides 1,813 GDD Excellent fit

Watercress Planting Timeline — Ransom County, ND

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 – Apr 10
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest June 19 Jun 19 – Jul 24
Fall Sowing July 11 Jul 11 – Jul 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4a

📆 Growing Season

148 days in Ransom County

Growing Tips for Watercress in Ransom County

Direct sow Watercress outdoors after May 08 in Ransom 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.

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 Ransom County, ND?

Ransom County is in Zone 4a with an average last frost of May 8. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ransom County, ND?

Ransom County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 8 and first fall frost is October 3.

🌱

Your Ransom County Garden Planner — Free

A 24-page printable planner built for Ransom County (Zone 4a). 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 Ransom County, ND. 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.