When to plant Vinca (Annual) in Doniphan County, KS
In Doniphan County, Vinca (Annual) is a single-season spring crop — there's no second fall window. Plant April 24–May 8 for an 70–90-day harvest, finishing well before the October 18 first frost.
When to Plant Vinca (Annual) in Doniphan County, KS
Top priorities for Doniphan County, Kansas gardeners in July
July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Doniphan County, Kansas.
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It's harvest week for vinca (annual)
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
Looking ahead to August
- First harvests: vinca (annual)
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.
Doniphan County, Kansas is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 18, giving you a growing season of approximately 184 days.
At an elevation of 491 feet, Doniphan County receives approximately 26.7 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Vinca (Annual) during the growing season.
Doniphan County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.3
Drainage
Well Drained
Vinca (Annual) Planting Risk Windows
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 Doniphan County
How your county's soil matches Vinca (Annual)'s growing requirements.
Soil pH
Your soil pH (6.8–7.3) 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 Doniphan 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 (4.1%) — Vinca (Annual) will thrive.
How to Plant Vinca (Annual)
Succession Planting Vinca (Annual)
Sow every 8 weeks. Last sowing by Jul 20 to harvest before frost.
Vinca (Annual) Water Budget
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 | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.7" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Nov | — | 0.8" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Doniphan 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) Planting Timeline — Doniphan County, KS
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 6 | Feb 6 – Feb 20 |
| Transplant Outdoors | April 24 | Apr 24 – May 8 |
| Bloom | July 3 | Jul 3 – Oct 9 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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: too_alkaline
🗺️ USDA Zone
Zone 6a
📆 Growing Season
184 days in Doniphan County
Growing Tips for Vinca (Annual) in Doniphan County
Direct sow Vinca (Annual) outdoors after April 17 in Doniphan 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 →
Vinca (Annual) in Other Locations
Frequently Asked Questions
When should I plant Vinca (Annual) in Doniphan County, KS?
Doniphan County is in Zone 6a with an average last frost of April 17. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Doniphan County, KS?
Doniphan County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 18.
When should I plant Vinca (Annual) in Doniphan County, KS?
In Doniphan County, KS, plant Vinca (Annual) after the last frost (around April 17) and before the first frost (around October 18). Best results when soil holds above 50°F.
What growing zone is Doniphan County, KS for Vinca (Annual)?
Doniphan County sits in USDA Zone 6a. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.
Can Vinca (Annual) grow in Doniphan County's climate?
Yes — Vinca (Annual) grows well in Doniphan County's temperate climate. Doniphan County averages a 184-day frost-free season, with last frost around April 17 and first frost around October 18.
Your Doniphan County Garden Planner — Free
A 22-page printable planner built for Doniphan County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.