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When to Plant Zucchini in San Juan County, UT

Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

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 Zucchini to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Zucchini 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 (48 days to spare)
Start indoors: Mar 16 Transplant: May 4 🍅 Harvest: Jun 22 – Aug 17
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Jul 4 – Aug 29
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Apr 21 Transplant: Jun 9 🍅 Harvest: Jul 28 – Sep 22

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
1.0″/week
Rainfall provides
0.4″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,116 gal / 100 sq ft
Drought risk

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

Zucchini needs ~682 GDD — county provides 2,106 GDD Excellent fit

Zucchini Planting Timeline โ€” San Juan County, UT

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 โ€“ Apr 11
Transplant Outdoors May 16 May 16 โ€“ May 30
Direct Sow May 9 May 9 โ€“ May 30
Harvest July 4 Jul 4 โ€“ Aug 29

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

45โ€“60 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

162 days

Growing Tips for San Juan County

Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Zucchini in San Juan County, UT?

San Juan County is in Zone 5b with an average last frost of May 2. Plan your Zucchini 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.

๐ŸŒฑ

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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Free download. Plan your entire garden season in minutes.

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.