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When to Plant Sweet Pea in Cache County, UT

Sweet peas (Lathyrus odoratus) are beloved cool-season climbing annuals grown primarily for their intensely fragrant, ruffled blooms in shades of pink, purple, red, and white. They thrive in cool spring conditions, climbing trellises to 4–6 feet, and make outstanding cut flowers. Bloom ceases once summer heat arrives, making early sowing critical for a long cutting season.

Cache County, Utah is in USDA Zone 6a. The average last spring frost is June 11 and the first fall frost is September 2, giving you a growing season of approximately 83 days.

At an elevation of 6,265 feet, Cache County receives approximately 15.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Sweet Pea to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Sweet Pea successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Spring Pollinator-friendly Good for cutting Fragrant
Cache County, UT (Zone 6a) Very short season
83 days
Last Spring Frost June 11
83 growing days
First Fall Frost September 2

Cache County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Monthly Watering Guide for Sweet Pea

Sweet Pea needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Sweet Pea Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2" 0" ❄️ Dormant
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.3" 3" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Cache County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sweet Pea Planting Timeline — Cache County, UT

Sweet Pea Planting Calendar

Activity When Date Range
Start Indoors April 30 Apr 30 – May 14
Transplant Outdoors June 11 Jun 11 – Jun 25
Direct Sow May 7 May 7 – May 28
Bloom August 27 Aug 27 – Nov 5

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Direct Sow
June Transplant Outdoors
July
August Bloom
September Bloom
October Bloom
November Bloom
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 7–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

83 days in Cache County

Growing Tips for Cache County

Soak seeds 24 hours before sowing to soften the hard seed coat; nick the seed coat with a file for the fastest germination. In cold zones (2–6), direct-sow as soon as soil can be worked, 4–6 weeks before last frost; seedlings tolerate light frost but not a hard freeze. In zones 7–9, fall-sow 8–10 weeks before first frost for earlier, stronger spring bloom. Provide a trellis or netting from the start. Feed with low-nitrogen, high-potassium fertilizer once buds form. Pick blooms regularly — even one mature seed pod stops flower production. All plant parts are mildly toxic if eaten.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Pea in Cache County, UT?

Cache County is in Zone 6a with an average last frost of June 11. Plan your Sweet Pea planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cache County, UT?

Cache County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is June 11 and first fall frost is September 2.

🌱

Your Cache County Garden Planner — Free

A 22-page printable planner built for Cache County (Zone 6a). 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 Cache County, UT. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.