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

In McPherson County, Vinca (Annual) is a spring-only crop. Plant April 22–May 6 once soil hits 50°F.

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

McPherson County, Kansas Zone 6b July

What to do in July

We've pulled the most time-sensitive tasks for McPherson County, Kansas this July and put them front and centre. Tackle them in order.

Avg. last frost April 15
Avg. first frost October 23
Soil temp (4") 81°F
Watering Moderate
Pest pressure High
Daylight 14.4 hrs
  1. Start harvesting vinca (annual)

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this July that'll pay off in August
  • 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.

McPherson County, Kansas is in USDA Zone 6b. The average last spring frost is April 15 and the first fall frost is October 23, giving you a growing season of approximately 191 days.

At an elevation of 850 feet, McPherson County receives approximately 27.1 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
McPherson County, KS (Zone 6b) Moderate season
191 days
Last Spring Frost April 15
191 growing days
First Fall Frost October 23

McPherson County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.6

Drainage

Well Drained

Vinca (Annual) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Start indoors: Feb 1 Transplant: Apr 19 🌸 Bloom: Jun 28 – Oct 11
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Feb 4 Transplant: Apr 22 🌸 Bloom: Jul 1 – Oct 14
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: Feb 16 Transplant: May 4 🌸 Bloom: Jul 13 – Oct 26

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 McPherson County

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

Soil pH

Your soil pH (6.4–7.6) overlaps with Vinca (Annual)'s range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Vinca (Annual).

Organic Matter

Organic matter is excellent (4.3%) — 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 191-day season

Sow every 8 weeks. Last sowing by Jul 25 to harvest before frost.

Vinca (Annual) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 110 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 0.6" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.2" 2.6" 0" ✅ Rainfall sufficient
May 2.2" 4.2" 0" ✅ Rainfall sufficient
Jun 2.2" 4.3" 0" ✅ Rainfall sufficient
Jul 2.2" 3.3" 0" ✅ Rainfall sufficient
Aug 2.2" 3.4" 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 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in McPherson 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 3,342 GDD Excellent fit

Vinca (Annual) Planting Timeline — McPherson County, KS

Vinca (Annual) Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 – Feb 18
Transplant Outdoors April 22 Apr 22 – May 6
Bloom July 1 Jul 1 – 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 Transplant Outdoors
June
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 6b

📆 Growing Season

191 days in McPherson County

Growing Tips for Vinca (Annual) in McPherson County

Direct sow Vinca (Annual) outdoors after April 15 in McPherson 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 McPherson County, KS?

McPherson County is in Zone 6b 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 McPherson County, KS?

McPherson County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 15 and first fall frost is October 23.

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

In McPherson County, KS, plant Vinca (Annual) after the last frost (around April 15) and before the first frost (around October 23). Best results when soil holds above 50°F.

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

McPherson 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 McPherson County's climate?

Yes — Vinca (Annual) grows well in McPherson County's temperate climate. McPherson County averages a 191-day frost-free season, with last frost around April 15 and first frost around October 23.

🌱

Your McPherson County Garden Planner — Free

A 22-page printable planner built for McPherson 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 McPherson County, KS. Local conditions may vary. Last updated: July 2026.

Sources & credits

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