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When to plant Dianthus in Monroe County, IA

Aim to plant Dianthus in Monroe County on or after March 29; the window stays open through April 19. Monroe County's 170-day frost-free season gives you a single solid spring crop with a brief fall option.

When to Plant Dianthus in Monroe County, IA

Monroe County, Iowa Zone 5b June

Top priorities for Monroe County, Iowa gardeners in June

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

Avg. last frost April 26
Avg. first frost October 13
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Start dianthus under lights

    These need a head start before your last frost (April 26). Sow into cells now so you're ready to transplant in a few weeks.

  2. Bring in the dianthus

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

Looking ahead to July
  • 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.

Monroe County, Iowa is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.

At an elevation of 968 feet, Monroe County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Dianthus during the growing season.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Monroe County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 26
170 growing days
First Fall Frost October 13

Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Dianthus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Feb 14 Transplant: Apr 4 🌸 Bloom: May 23 – Aug 15
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Feb 22 Transplant: Apr 12 🌸 Bloom: May 31 – Aug 23
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 17 – Sep 9

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 Monroe County

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

Soil pH

Your soil pH (6.2–7.3) is within Dianthus's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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 170-day season

Sow every 6.9 weeks. Last sowing by Jul 25 to harvest before frost.

Dianthus Water Budget

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

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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 3.3" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 2.1" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Monroe 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 ~1,068 GDD — county provides 2,592 GDD Excellent fit

Dianthus Planting Timeline — Monroe County, IA

Dianthus Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 – Mar 8
Transplant Outdoors April 12 Apr 12 – Apr 26
Direct Sow March 29 Mar 29 – Apr 19
Bloom May 31 May 31 – Aug 23

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Bloom
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 5b

📆 Growing Season

170 days in Monroe County

Growing Tips for Dianthus in Monroe County

Direct sow Dianthus outdoors after April 26 in Monroe 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 Monroe County, IA?

Monroe County is in Zone 5b with an average last frost of April 26. Plan your Dianthus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, IA?

Monroe County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 13.

When should I plant Dianthus in Monroe County, IA?

In Monroe County, IA, plant Dianthus after the last frost (around April 26) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Monroe County, IA for Dianthus?

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

Can Dianthus grow in Monroe County's climate?

Yes — Dianthus grows well in Monroe County's temperate climate. Monroe County averages a 170-day frost-free season, with last frost around April 26 and first frost around October 13.

🌱

Your Monroe County Garden Planner — Free

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

Sources & credits

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