When to plant Vinca (Annual) in Calhoun County, AL
In Calhoun County, Vinca (Annual) is a single-season spring crop — there's no second fall window. Plant March 24–April 7 for an 70–90-day harvest, finishing well before the October 31 first frost.
When to Plant Vinca (Annual) in Calhoun County, AL
August in the garden — Calhoun County, Alabama
Here's what deserves your attention in Calhoun County, Alabama this month. Everything below is tailored to Zone 8a and timed around your local frost dates.
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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 September
- 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.
Calhoun County, Alabama is in USDA Zone 8a. The average last spring frost is March 31 and the first fall frost is October 31, giving you a growing season of approximately 214 days.
At an elevation of 440 feet, Calhoun County receives approximately 52.2 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°F, providing good warmth for Vinca (Annual) during the growing season. Clay soil retains moisture well for Vinca (Annual), but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Vinca (Annual) root diseases.
Calhoun County Soil Profile
Soil Type
Clay Loam
Soil pH
5.3-6.4
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 Calhoun County
How your county's soil matches Vinca (Annual)'s growing requirements.
Soil pH
Your soil pH (5.3–6.4) is more acidic than Vinca (Annual) prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The clay loam soil in Calhoun County is excellent for Vinca (Annual) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Vinca (Annual).
How to Plant Vinca (Annual)
Succession Planting Vinca (Annual)
Sow every 8 weeks. Last sowing by Aug 02 to harvest before frost.
Vinca (Annual) Water Budget
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 | — | 4" | 0" | ❄️ Dormant |
| Feb | — | 3.7" | 0" | ❄️ Dormant |
| Mar | 2.2" | 5.7" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 5.4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 5.1" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 4.2" | 0" | ❄️ Dormant |
| Dec | — | 4.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Oct in Calhoun 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 — Calhoun County, AL
Vinca (Annual) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 20 | Jan 20 – Feb 3 |
| Transplant Outdoors | March 24 | Mar 24 – Apr 7 |
| Bloom | June 2 | Jun 2 – Oct 20 |
Plant 0.1" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors |
| March | Transplant Outdoors |
| 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 · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8a
📆 Growing Season
214 days in Calhoun County
Growing Tips for Vinca (Annual) in Calhoun County
Direct sow Vinca (Annual) outdoors after March 31 in Calhoun County when soil has warmed and frost danger has passed.
With Calhoun County's clay soil (27% clay), work in 3-4 inches of compost before planting Vinca (Annual). Avoid tilling when soil is wet to prevent compaction.
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 Calhoun County, AL?
Calhoun County is in Zone 8a with an average last frost of March 31. Plan your Vinca (Annual) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Calhoun County, AL?
Calhoun County, Alabama is in USDA Hardiness Zone 8a. The average last spring frost is March 31 and first fall frost is October 31.
When should I plant Vinca (Annual) in Calhoun County, AL?
In Calhoun County, AL, plant Vinca (Annual) after the last frost (around March 31) and before the first frost (around October 31). Best results when soil holds above 50°F.
What growing zone is Calhoun County, AL for Vinca (Annual)?
Calhoun County sits in USDA Zone 8a. Vinca (Annual) grows reliably in zones 3a through 11b, so it's a good fit here.
Can Vinca (Annual) grow in Calhoun County's climate?
Yes — Vinca (Annual) grows well in Calhoun County's temperate climate. Calhoun County averages a 214-day frost-free season, with last frost around March 31 and first frost around October 31.
Your Calhoun County Garden Planner — Free
A 22-page printable planner built for Calhoun County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.