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When to Plant Watercress in Clearwater County, MN

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.

Clearwater County, Minnesota is in USDA Zone 3b. The average last spring frost is May 15 and the first fall frost is September 28, giving you a growing season of approximately 136 days.

At an elevation of 1,074 feet, Clearwater County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Watercress to ensure they mature before fall.

Clearwater County, MN (Zone 3b) Short season
136 days
Last Spring Frost May 15
136 growing days
First Fall Frost September 28

Clearwater County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Mar 27 Transplant: May 8 🍅 Harvest: Jun 19 – Jul 24
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Jun 26 – Jul 31
Safe Start (90%) ✓ Fits season (61 days to spare)
Start indoors: Apr 16 Transplant: May 28 🍅 Harvest: Jul 9 – Aug 13

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,321 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Watercress needs ~500 GDD — county provides 1,360 GDD Excellent fit

Watercress Planting Timeline โ€” Clearwater County, MN

Watercress Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 โ€“ Apr 17
Transplant Outdoors May 15 May 15 โ€“ May 29
Direct Sow May 8 May 8 โ€“ May 29
Fall Sowing July 6 Jul 6 โ€“ Jul 20
Harvest June 26 Jun 26 โ€“ Jul 31

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

40โ€“60 days

Soil pH

6.5 โ€“ 7.5

USDA Zone

Zone 3b

Growing Season

136 days

Growing Tips for Clearwater County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Watercress in Clearwater County, MN?

Clearwater County is in Zone 3b with an average last frost of May 15. Plan your Watercress planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clearwater County, MN?

Clearwater County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 15 and first fall frost is September 28.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clearwater County gardeners in Zone 3b organize planting dates, track what's growing, and never miss a planting window.

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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 Clearwater County, MN. Local conditions may vary. Last updated: April 2026.