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When to Plant Marigolds in Weber County, UT

Weber County, Utah Zone 7a August

August to-do list for Weber County, Utah

August is a pivotal month for Weber County, Utah gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 26
Avg. first frost September 21
Soil temp (4") 66°F
Watering High
Pest pressure High
Daylight 13.7 hrs
  1. Pick marigolds

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

September will be here before you know it — start on
  • First harvests: marigolds

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Marigolds (Tagetes patula) are warm-season annuals beloved for their cheerful orange, yellow, and red blooms — and for their well-documented ability to repel pest nematodes in vegetable beds. Easy from seed, drought-tolerant once established, and bloom from early summer until the first hard frost.

Weber County, Utah is in USDA Zone 7a. The average last spring frost is May 26 and the first fall frost is September 21, giving you a growing season of approximately 118 days.

At an elevation of 6,211 feet, Weber County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Marigolds during the growing season. With low rainfall, drip irrigation is essential for growing Marigolds successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Weber County, UT (Zone 7a) Short season
118 days
Last Spring Frost May 26
118 growing days
First Fall Frost September 21

Weber County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Marigolds Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 26 Transplant: May 7 🌸 Bloom: Jul 2 – Oct 8
Recommended (50%) ✗ May not fit
Start indoors: Apr 14 Transplant: May 26 🌸 Bloom: Jul 21 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: May 8 Transplant: Jun 19 🌸 Bloom: Aug 14 – Nov 20

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 Weber County

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

Soil pH

Your soil pH (6.6–7.7) overlaps with Marigolds's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Marigolds

0.3"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Marigolds

2
successive plantings in your 118-day season

Sow every 5.7 weeks. Last sowing by Jul 13 to harvest before frost.

Marigolds Water Budget

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

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Marigolds

Marigolds 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 Marigolds Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.2" 2.1" 0.1" 💧 Light watering
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 1.5" 0.7" 💧 Light watering
Aug 2.2" 2.2" 0" ✅ Rainfall sufficient
Sep 2.2" 1.5" 0.7" 💧 Light watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Marigolds 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.

Marigolds needs ~870 GDD — county provides 1,711 GDD Excellent fit

Marigolds Planting Timeline — Weber County, UT

Marigolds Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 – Apr 28
Transplant Outdoors May 26 May 26 – Jun 9
Direct Sow May 26 May 26 – Jun 16
Bloom July 21 Jul 21 – Oct 27

Plant 0.3" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

118 days in Weber County

Growing Tips for Marigolds in Weber County

Direct sow Marigolds outdoors after May 26 in Weber County when soil has warmed and frost danger has passed.

Common pests for Marigolds in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct-sow after last frost or start indoors 4-6 weeks earlier. Deadhead spent blooms to keep new flowers coming. French marigolds (T. patula) are the most reliable nematode repellents — plant a band around vegetable beds. Tolerate poor soil but bloom best with monthly compost.

Companion Planting

Good Companions

Avoid Planting Near

  • Beans
  • Cabbage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Marigolds Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower heads dry on plant. Pull dried petals to reveal seeds.
Storage Store in envelopes; viable 3 years at 35°F, under 50% humidity.

Very easy to save. Seeds are the long, thin, dark pieces inside the dried flower head.

Frequently Asked Questions

When should I plant Marigolds in Weber County, UT?

Weber County is in Zone 7a with an average last frost of May 26. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.

What planting zone is Weber County, UT?

Weber County, Utah is in USDA Hardiness Zone 7a. The average last spring frost is May 26 and first fall frost is September 21.

🌱

Your Weber County Garden Planner — Free

A 22-page printable planner built for Weber County (Zone 7a). 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 Weber County, UT. Local conditions may vary. Last updated: August 2026.

Sources & credits

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