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When to plant Vinca (Annual) in Coffey County County,

Coffey County County's short 196-day growing season means one Vinca (Annual) planting between April 18 and May 2. No fall crop in Zone 6b.

When to Plant Vinca (Annual) in Coffey County, KS

Coffey County, Kansas Zone 6b June

June in Coffey County, Kansas — your action list

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

Avg. last frost April 11
Avg. first frost October 24
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Indoor seed-starting week for vinca (annual)

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Basket week: vinca (annual)

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

July prep starts now
  • First harvests: vinca (annual)

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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.

Coffey County, Kansas is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 24, giving you a growing season of approximately 196 days.

At an elevation of 466 feet, Coffey County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Vinca (Annual) during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Coffey County, KS (Zone 6b) Moderate season
196 days
Last Spring Frost April 11
196 growing days
First Fall Frost October 24

Coffey County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Jan 25 Transplant: Apr 12 🌸 Bloom: Jun 21 – Oct 4
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Jan 31 Transplant: Apr 18 🌸 Bloom: Jun 27 – Oct 10
Safe Start (90%) ✓ Fits season (19 days to spare)
Start indoors: Feb 11 Transplant: Apr 29 🌸 Bloom: Jul 8 – Oct 21

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 Coffey County

How your county's soil matches Vinca (Annual)'s growing requirements.

Soil pH

Your soil pH (6.5–7.7) is more alkaline than Vinca (Annual) prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). 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)

3
successive plantings in your 196-day season

Sow every 8 weeks. Last sowing by Jul 26 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 0.7" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.2" 3.1" 0" ✅ Rainfall sufficient
May 2.2" 4.1" 0" ✅ Rainfall sufficient
Jun 2.2" 3.9" 0" ✅ Rainfall sufficient
Jul 2.2" 3.4" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.9" 0" ✅ Rainfall sufficient
Oct 2.2" 1.6" 0.6" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Coffey 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 ~1,220 GDD — county provides 2,989 GDD Excellent fit

Vinca (Annual) Planting Timeline — Coffey County, KS

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors April 18 Apr 18 – May 2
Bloom June 27 Jun 27 – Oct 10

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March
April Transplant Outdoors
May Transplant Outdoors
June Bloom
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

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

196 days in Coffey County

Growing Tips for Vinca (Annual) in Coffey County

Direct sow Vinca (Annual) outdoors after April 11 in Coffey 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 Coffey County, KS?

Coffey County is in Zone 6b with an average last frost of April 11. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Coffey County, KS?

Coffey County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 24.

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

In Coffey County, , plant Vinca (Annual) after the last frost (around April 11) and before the first frost (around October 24). Best results when soil holds above 50°F.

What growing zone is Coffey County, for Vinca (Annual)?

Coffey County sits in USDA Zone 6b. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.

Can Vinca (Annual) grow in Coffey County's climate?

Yes — Vinca (Annual) grows well in Coffey County's temperate climate. Coffey County averages a 196-day frost-free season, with last frost around April 11 and first frost around October 24.

🌱

Your Coffey County Garden Planner — Free

A 22-page printable planner built for Coffey 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.

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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 Coffey County, KS. 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.