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When to Plant Watercress in Big Stone 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.

Big Stone County, Minnesota is in USDA Zone 4a. The average last spring frost is May 2 and the first fall frost is October 4, giving you a growing season of approximately 155 days.

At an elevation of 823 feet, Big Stone County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Watercress to ensure they mature before fall.

Big Stone County, MN (Zone 4a) Moderate season
155 days
Last Spring Frost May 2
155 growing days
First Fall Frost October 4

Big Stone County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jun 8 – Jul 13
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Jun 13 – Jul 18
Safe Start (90%) ✓ Fits season (77 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jun 25 – Jul 30

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
0.9″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 1,770 gal / 100 sq ft
Drought risk

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

Watercress needs ~538 GDD — county provides 1,666 GDD Excellent fit

Watercress Planting Timeline โ€” Big Stone County, MN

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 โ€“ Apr 4
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 25 Apr 25 โ€“ May 16
Fall Sowing July 12 Jul 12 โ€“ Jul 26
Harvest June 13 Jun 13 โ€“ Jul 18

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors Direct Sow
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 4a

Growing Season

155 days

Growing Tips for Big Stone 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 Big Stone County, MN?

Big Stone County is in Zone 4a with an average last frost of May 2. Plan your Watercress planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Big Stone County, MN?

Big Stone County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 2 and first fall frost is October 4.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Big Stone County gardeners in Zone 4a 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 Big Stone County, MN. Local conditions may vary. Last updated: April 2026.