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When to Plant Nasturtium in Cache Junction, UT

Cache County, Utah Zone 6a August

Your August planting checklist for Cache County, Utah

If you only do a handful of things in the garden this August, make it these. They're sequenced around your zone's frost timing.

Avg. last frost June 11
Avg. first frost September 2
Soil temp (4") 59°F
Watering High
Pest pressure High
Daylight 13.7 hrs
  1. Bring in the nasturtium

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of September
  • First harvests: nasturtium

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Nasturtium (Tropaeolum majus) is a fast-growing annual with distinctive round, lily-pad leaves and bold trumpet-shaped blooms in warm oranges, reds, and yellows. Both the flowers and leaves are edible with a peppery watercress flavor. Planted near vegetables, nasturtiums act as a sacrifice trap-crop, luring aphids away from more valuable plants. They thrive in poor, dry soil — rich conditions produce lush foliage but few flowers.

Cache Junction, 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 Nasturtium to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Nasturtium successfully. Mulch heavily to conserve soil moisture.

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

Cache Junction Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 17 Transplant: May 22 🌸 Bloom: Jul 17 – Nov 6
Recommended (50%) ✗ May not fit
Start indoors: May 14 Transplant: Jun 18 🌸 Bloom: Aug 13 – Dec 3
Safe Start (90%) ✗ May not fit
Start indoors: May 27 Transplant: Jul 1 🌸 Bloom: Aug 26 – Dec 16

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.

Soil Compatibility in Cache Junction

How your county's soil matches Nasturtium's growing requirements.

Soil pH

Your soil pH (6.6–8.4) overlaps with Nasturtium's range (6.0–8.0), though not a perfect match.

Soil Texture

The loam soil in Cache County is excellent for Nasturtium — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Nasturtium.

How to Plant Nasturtium

0.5"
Planting Depth
10"
Between Plants
12"
Between Rows

Nasturtium Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Nasturtium

Nasturtium needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Nasturtium 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 2.2" 1.1" 1.1" 🚿 Regular watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light 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.

Nasturtium Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Nasturtium needs ~780 GDD — county provides 1,079 GDD Excellent fit

Nasturtium Planting Timeline — Cache Junction, UT

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors May 14 May 14 – May 28
Transplant Outdoors June 18 Jun 18 – Jul 2
Direct Sow June 18 Jun 18 – Jul 9
Bloom August 13 Aug 13 – Dec 3

Plant 0.5" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

55–65 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

83 days in Cache County

Growing Tips for Nasturtium in Cache Junction

Direct sow Nasturtium outdoors after June 11 in Cache County when soil has warmed and frost danger has passed.

Cache County receives only 16" of rain annually. Nasturtium needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow large seeds 1/2 inch deep after last frost; soak seeds overnight to speed germination (7-10 days). Nasturtiums dislike root disturbance so direct sowing is strongly preferred. Avoid fertilizing — poor soil brings the best bloom. Trailing types can cover banks and climb trellises; dwarf types suit containers. In hot climates (zones 9+) plant in fall for winter/spring bloom as plants struggle in peak summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

🌱

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: August 2026.