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When to plant Dianthus in Marshall County, IA

Marshall County gardeners should plant Dianthus between April 4 and April 25 in spring. With Marshall County's Zone 5a climate (last frost May 2), Dianthus needs 60–80 days to mature — plant by July 19 for a full harvest.

When to Plant Dianthus in Marshall County, IA

Marshall County, Iowa Zone 5a June

Your June gardening checklist

Each item below is timed to Marshall County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 2
Avg. first frost October 7
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. It's harvest week for dianthus

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Coming up in July — start thinking about
  • Starting indoors: dianthus
  • First harvests: dianthus

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China pinks (Dianthus chinensis) are a reliable cool-season annual offering fringed blooms with a spicy-sweet clove fragrance. They perform best in the cool temperatures of spring and fall, providing vivid color in beds and borders when summer annuals haven't kicked in yet. In warmer zones they are grown as fall–winter–spring annuals. The compact mounding habit and clean foliage make them excellent edging and container plants.

Marshall County, Iowa is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 1,379 feet, Marshall County receives approximately 33.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Dianthus to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Marshall County, IA (Zone 5a) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Marshall County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Dianthus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🌸 Bloom: May 28 – Aug 13
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Feb 28 Transplant: Apr 18 🌸 Bloom: Jun 6 – Aug 22
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 17 – Sep 2

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 Marshall County

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

Soil pH

Your soil pH (6.2–7.1) is within Dianthus's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Dianthus will thrive.

How to Plant Dianthus

0.1"
Planting Depth
8"
Between Plants
10"
Between Rows

Succession Planting Dianthus

3
successive plantings in your 158-day season

Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.

Dianthus Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Dianthus

Dianthus 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 Dianthus Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.7" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 2.3" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

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

Dianthus 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.

Dianthus needs ~858 GDD — county provides 1,935 GDD Excellent fit

Dianthus Planting Timeline — Marshall County, IA

Dianthus Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 4 Apr 4 – Apr 25
Bloom June 6 Jun 6 – Aug 22

Plant 0.1" deep · 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

158 days in Marshall County

Growing Tips for Dianthus in Marshall County

Direct sow Dianthus outdoors after May 02 in Marshall County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 8–10 weeks before last frost for spring transplants, or direct-sow in early spring as soon as soil can be worked — seeds tolerate light frost. Can also be direct-sown in late summer for fall bloom. Plant in full sun with excellent drainage; poorly drained soil causes crown rot. Deadhead regularly to extend bloom. In zones 8–10, plant as a fall annual for winter– spring color; plants decline in summer heat.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Dianthus in Marshall County, IA?

Marshall County is in Zone 5a with an average last frost of May 2. Plan your Dianthus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, IA?

Marshall County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.

When should I plant Dianthus in Marshall County, IA?

In Marshall County, IA, plant Dianthus after the last frost (around May 2) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Marshall County, IA for Dianthus?

Marshall County sits in USDA Zone 5a. Dianthus grows reliably in zones 3a through 10b, so it's a good fit here.

Can Dianthus grow in Marshall County's climate?

Yes — Dianthus grows well in Marshall County's temperate climate. Marshall County averages a 158-day frost-free season, with last frost around May 2 and first frost around October 7.

🌱

Your Marshall County Garden Planner — Free

A 22-page printable planner built for Marshall County (Zone 5a). 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 Marshall County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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