Blog

When to Plant Vinca (Annual) in Monroe County, OH

Monroe County, Ohio Zone 6b June

Your June planting checklist for Monroe County, Ohio

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

Avg. last frost April 27
Avg. first frost October 20
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
Coming up in July — start thinking about
  • Starting indoors: vinca (annual)
  • First harvests: vinca (annual)

Instant PDF download. No spam, unsubscribe any time.

Annual vinca (Catharanthus roseus), also called Madagascar periwinkle, is one of the most heat- and drought-tolerant bedding plants available. Glossy foliage stays attractive all season while cheerful pinwheel blooms continue without deadheading. A top performer in hot, humid Southern summers where impatiens and begonias struggle. Self-cleaning; requires little maintenance once established.

Monroe County, Ohio is in USDA Zone 6b. The average last spring frost is April 27 and the first fall frost is October 20, giving you a growing season of approximately 176 days.

At an elevation of 567 feet, Monroe County receives approximately 31.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Vinca (Annual) during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Monroe County, OH (Zone 6b) Moderate season
176 days
Last Spring Frost April 27
176 growing days
First Fall Frost October 20
Share this guide:

Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 11 Transplant: Apr 29 🌸 Bloom: Jul 8 – Oct 21
Recommended (50%) ✗ May not fit
Start indoors: Feb 16 Transplant: May 4 🌸 Bloom: Jul 13 – Oct 26
Safe Start (90%) ✗ May not fit
Start indoors: Mar 7 Transplant: May 23 🌸 Bloom: Aug 1 – Nov 14

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 Vinca (Annual)'s growing requirements.

Soil pH

Your soil pH (5.8–6.9) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (4.0%). Annual compost additions will help Vinca (Annual).

How to Plant Vinca (Annual)

0.1"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Vinca (Annual)

2
successive plantings in your 176-day season

Sow every 8 weeks. Last sowing by Jul 22 to harvest before frost.

Vinca (Annual) 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 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Vinca (Annual)

Vinca (Annual) 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 Vinca (Annual) Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 3.4" 0" ✅ Rainfall sufficient
Jun 2.2" 3.9" 0" ✅ Rainfall sufficient
Jul 2.2" 3.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 3.1" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 1.9" 0" ❄️ Dormant
Dec 1.5" 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.

Vinca (Annual) 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.

Vinca (Annual) needs ~1,100 GDD — county provides 2,420 GDD Excellent fit

Vinca (Annual) Planting Timeline — Monroe County, OH

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors May 4 May 4 – May 18
Bloom July 13 Jul 13 – Oct 26

Plant 0.1" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April
May Transplant Outdoors
June
July Bloom
August Bloom
September Bloom
October Bloom
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

176 days in Monroe County

Growing Tips for Vinca (Annual) in Monroe County

Direct sow Vinca (Annual) outdoors after April 27 in Monroe County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 10–12 weeks before last frost — germination requires warm soil (75–80°F) and darkness. Do not cover seeds deeply; they need just a light dusting. Direct sowing is rarely practiced due to slow seedling establishment. Transplant after soil warms and frost danger has passed. Excellent drought tolerance once established; avoid overwatering. Performs best in well-drained beds or containers in full sun.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Vinca (Annual) in Monroe County, OH?

Monroe County is in Zone 6b with an average last frost of April 27. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, OH?

Monroe County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 27 and first fall frost is October 20.

🌱

Your Monroe County Garden Planner — Free

A 22-page printable planner built for Monroe County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Monroe County, OH. 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.