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When to plant Vinca (Annual) in Barber County, KS

In Barber County, Vinca (Annual) is a spring-only crop. Plant April 15–April 29 once soil hits 50°F.

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

Barber County, Kansas Zone 7a June

Your June game plan for Barber County, Kansas

Your Barber County, Kansas garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 15
Avg. first frost October 24
Soil temp (4") 74°F
Watering Moderate
Pest pressure High
Daylight 14.5 hrs
  1. Fire up the seed-starting tray: vinca (annual)

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Harvest vinca (annual) as they ripen

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to July
  • 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.

Barber County, Kansas is in USDA Zone 7a. The average last spring frost is April 15 and the first fall frost is October 24, giving you a growing season of approximately 192 days.

At an elevation of 964 feet, Barber County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Vinca (Annual) during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant
Barber County, KS (Zone 7a) Moderate season
192 days
Last Spring Frost April 15
192 growing days
First Fall Frost October 24

Barber County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.1

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Start indoors: Jan 29 Transplant: Apr 9 🌸 Bloom: Jun 18 – Oct 8
Recommended (50%) ✓ Fits season (10 days to spare)
Start indoors: Feb 4 Transplant: Apr 15 🌸 Bloom: Jun 24 – Oct 14
Safe Start (90%) ✓ Fits season (13 days to spare)
Start indoors: Feb 17 Transplant: Apr 28 🌸 Bloom: Jul 7 – Oct 27

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 Barber County

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

Soil pH

Your soil pH (6.6–7.1) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Vinca (Annual) will thrive.

How to Plant Vinca (Annual)

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

Succession Planting Vinca (Annual)

3
successive plantings in your 192-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
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 101 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 0.5" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2.2" 2.1" 0.1" 💧 Light watering
May 2.2" 3.4" 0" ✅ Rainfall sufficient
Jun 2.2" 3.2" 0" ✅ Rainfall sufficient
Jul 2.2" 2.4" 0" ✅ Rainfall sufficient
Aug 2.2" 2.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.1" 0.1" 💧 Light watering
Oct 2.2" 1.3" 0.9" 💧 Light watering
Nov 0.6" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Barber 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 ~1,400 GDD — county provides 3,360 GDD Excellent fit

Vinca (Annual) Planting Timeline — Barber County, KS

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 – Feb 18
Transplant Outdoors April 15 Apr 15 – Apr 29
Bloom June 24 Jun 24 – Oct 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

192 days in Barber County

Growing Tips for Vinca (Annual) in Barber County

Direct sow Vinca (Annual) outdoors after April 15 in Barber County when soil has warmed and frost danger has passed.

Barber County receives only 21" of rain annually. Vinca (Annual) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Barber County, KS?

Barber County is in Zone 7a with an average last frost of April 15. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Barber County, KS?

Barber County, Kansas is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 24.

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

In Barber County, KS, plant Vinca (Annual) after the last frost (around April 15) and before the first frost (around October 24). Best results when soil holds above 50°F.

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

Barber County sits in USDA Zone 7a. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.

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

Yes — Vinca (Annual) grows well in Barber County's temperate climate. Barber County averages a 192-day frost-free season, with last frost around April 15 and first frost around October 24.

🌱

Your Barber County Garden Planner — Free

A 22-page printable planner built for Barber 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 Barber 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.