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When to Plant Watercress in Wilkin County, MN

Wilkin County, Minnesota Zone 4a May

May to-do list for Wilkin County, Minnesota

Your Wilkin County, Minnesota garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 11
Avg. first frost September 30
Soil temp (4") 50°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Move watercress from tray to bed

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Put watercress seeds straight in the ground

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

To set up a strong June, finish these tasks
  • 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.

Wilkin County, Minnesota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 1,365 feet, Wilkin County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Watercress to ensure they mature before fall.

Wilkin County, MN (Zone 4a) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30

Wilkin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 20 Transplant: May 1 🍅 Harvest: Jun 12 – Jul 17
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jun 22 – Jul 27
Safe Start (90%) ✓ Fits season (69 days to spare)
Start indoors: Apr 9 Transplant: May 21 🍅 Harvest: Jul 2 – Aug 6

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 Wilkin County

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

Soil pH

Your soil pH (5.8–7.0) is more acidic than Watercress prefers (6.5–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Watercress is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is excellent (5.0%) — Watercress will thrive.

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 142-day season

Sow every 4.6 weeks. Last sowing by Aug 01 to harvest before frost.

For a dedicated fall crop, sow by Jul 08.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.2″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,163 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 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 6.5" 5" 1.5" 💧 Light watering
Jun 6.5" 5.5" 1" 💧 Light watering
Jul 6.5" 4.6" 1.9" 💧 Light watering
Aug 6.5" 3.8" 2.7" 💧 Light watering
Sep 6.5" 3.5" 3" 💧 Light watering
Oct 3.6" 0" ❄️ Dormant
Nov 2.8" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Wilkin 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 ~425 GDD — county provides 1,207 GDD Excellent fit

Watercress Planting Timeline — Wilkin County, MN

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 4 May 4 – May 25
Harvest June 22 Jun 22 – Jul 27
Fall Sowing July 8 Jul 8 – Jul 22

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 · 2-3 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4a

📆 Growing Season

142 days in Wilkin County

Growing Tips for Watercress in Wilkin County

Direct sow Watercress outdoors after May 11 in Wilkin 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 Wilkin County, MN?

Wilkin County is in Zone 4a with an average last frost of May 11. Plan your Watercress planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wilkin County, MN?

Wilkin County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is September 30.

🌱

Your Wilkin County Garden Planner — Free

A 24-page printable planner built for Wilkin 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 Wilkin County, MN. Local conditions may vary. Last updated: May 2026.

Sources & credits

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