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When to Plant Watercress in San Juan County, UT

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.

San Juan County, Utah is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 11, giving you a growing season of approximately 162 days.

At an elevation of 5,225 feet, San Juan County receives approximately 13.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Watercress to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Watercress successfully. Mulch heavily to conserve soil moisture.

San Juan County, UT (Zone 5b) Moderate season
162 days
Last Spring Frost May 2
162 growing days
First Fall Frost October 11

San Juan County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: Jun 1 – Jul 6
Recommended (50%) ✓ Fits season (85 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jun 13 – Jul 18
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Apr 21 Transplant: May 26 🍅 Harvest: Jul 7 – Aug 11

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
0.4″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 1,981 gal / 100 sq ft
Drought risk

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

Watercress needs ~650 GDD — county provides 2,106 GDD Excellent fit

Watercress Planting Timeline โ€” San Juan County, UT

Watercress Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 โ€“ Apr 11
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 18 Apr 18 โ€“ May 9
Fall Sowing August 2 Aug 2 โ€“ Aug 16
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 Harvest
August Fall Sowing
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 5b

Growing Season

162 days

Growing Tips for San Juan 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 San Juan County, UT?

San Juan County is in Zone 5b 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 San Juan County, UT?

San Juan County, Utah is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 11.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help San Juan County gardeners in Zone 5b 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 San Juan County, UT. Local conditions may vary. Last updated: April 2026.