When to plant Vinca (Annual) in Douglas County County,
Plant Vinca (Annual) in Douglas County County during the brief April 19–May 3 window. With 196 frost-free days, fall plantings can't mature before October 25.
When to Plant Vinca (Annual) in Douglas County, KS
Your June game plan for Douglas County, Kansas
We've pulled the most time-sensitive tasks for Douglas County, Kansas this June and put them front and centre. Tackle them in order.
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Sow vinca (annual) in trays indoors
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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Bring in the vinca (annual)
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
July prep starts now
- 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.
Douglas County, Kansas is in USDA Zone 6b. The average last spring frost is April 12 and the first fall frost is October 25, giving you a growing season of approximately 196 days.
At an elevation of 494 feet, Douglas County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Vinca (Annual) during the growing season.
Douglas County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.6
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 Douglas County
How your county's soil matches Vinca (Annual)'s growing requirements.
Soil pH
Your soil pH (6.5–7.6) 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 Douglas County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.2%). Annual compost additions will help Vinca (Annual).
How to Plant Vinca (Annual)
Succession Planting Vinca (Annual)
Sow every 8 weeks. Last sowing by Jul 27 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 | — | 0.7" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Douglas 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 — Douglas County, KS
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 1 | Feb 1 – Feb 15 |
| Transplant Outdoors | April 19 | Apr 19 – May 3 |
| Bloom | June 28 | Jun 28 – Oct 11 |
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 | 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 Douglas County
Growing Tips for Vinca (Annual) in Douglas County
Direct sow Vinca (Annual) outdoors after April 12 in Douglas 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 Douglas County, KS?
Douglas County is in Zone 6b with an average last frost of April 12. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Douglas County, KS?
Douglas County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 12 and first fall frost is October 25.
When should I plant Vinca (Annual) in Douglas County, ?
In Douglas County, , plant Vinca (Annual) after the last frost (around April 12) and before the first frost (around October 25). Best results when soil holds above 50°F.
What growing zone is Douglas County, for Vinca (Annual)?
Douglas 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 Douglas County's climate?
Yes — Vinca (Annual) grows well in Douglas County's temperate climate. Douglas County averages a 196-day frost-free season, with last frost around April 12 and first frost around October 25.
Your Douglas County Garden Planner — Free
A 22-page printable planner built for Douglas 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.