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When to Plant Marigolds in Chelan County, WA

Chelan County, Washington Zone 7a July

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Avg. last frost April 24
Avg. first frost October 20
Soil temp (4") 72°F
Watering Critical
Pest pressure High
Daylight 15.4 hrs
  1. Basket week: marigolds

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

August prep starts now
  • 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.

Chelan County, Washington is in USDA Zone 7a. The average last spring frost is April 24 and the first fall frost is October 20, giving you a growing season of approximately 179 days.

At an elevation of 3,517 feet, Chelan County receives approximately 14.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°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
Chelan County, WA (Zone 7a) Moderate season
179 days
Last Spring Frost April 24
179 growing days
First Fall Frost October 20

Chelan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Marigolds Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Mar 2 Transplant: Apr 13 🌸 Bloom: Jun 8 – Sep 14
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Mar 13 Transplant: Apr 24 🌸 Bloom: Jun 19 – Sep 25
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Apr 7 Transplant: May 19 🌸 Bloom: Jul 14 – Oct 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 Chelan County

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

Soil pH

Your soil pH (5.5–6.3) is more acidic than Marigolds prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Marigolds will thrive.

How to Plant Marigolds

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

Succession Planting Marigolds

4
successive plantings in your 179-day season

Sow every 5.7 weeks. Last sowing by Aug 11 to harvest before frost.

Marigolds Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 319 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 2.1" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 2.2" 1.2" 1" 💧 Light watering
May 2.2" 0.9" 1.3" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 0.2" 2" 🚿 Regular watering
Aug 2.2" 0.3" 1.9" 🚿 Regular watering
Sep 2.2" 0.5" 1.7" 🚿 Regular watering
Oct 2.2" 1.2" 1" 💧 Light watering
Nov 1.9" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Chelan 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 ~915 GDD — county provides 2,729 GDD Excellent fit

Marigolds Planting Timeline — Chelan County, WA

Marigolds Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 24 Apr 24 – May 15
Bloom June 19 Jun 19 – Sep 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

179 days in Chelan County

Growing Tips for Marigolds in Chelan County

Direct sow Marigolds outdoors after April 24 in Chelan 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 Chelan County, WA?

Chelan County is in Zone 7a with an average last frost of April 24. Plan your Marigolds planting based on this frost date — see the calendar above for exact timing.

What planting zone is Chelan County, WA?

Chelan County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 24 and first fall frost is October 20.

🌱

Your Chelan County Garden Planner — Free

A 22-page printable planner built for Chelan 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 Chelan County, WA. 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.