Blog

When to plant Dahlias in Colbert County County,

For Colbert County County, gardeners: plant Dahlias April 6 through April 27 once soil reads 50°F.

When to Plant Dahlias in Colbert County, AL

Colbert County, Alabama Zone 8a June

This month in Colbert County, Alabama

Welcome to June in Zone 8a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 6
Avg. first frost October 28
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 14.3 hrs
  1. Bring in the dahlias

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

July will be here before you know it — start on
  • First harvests: dahlias

Instant PDF download. No spam, unsubscribe any time.

Dahlias (Dahlia spp.) are the undisputed stars of the late-summer and fall garden, producing an extraordinary range of flower forms — from compact pompons to dinner plate-sized blooms spanning 12 inches — in virtually every color except true blue. Blooming from midsummer until the first hard frost, a single tuber grows into a massive, flower-laden plant that can produce dozens of cut flowers per week. Modern breeding has expanded the palette and forms dramatically; the American Dahlia Society recognizes over 20 flower forms. Extremely rewarding for gardeners willing to invest in the planting, staking, and (in cold zones) annual lifting of tubers.

Colbert County, Alabama is in USDA Zone 8a. The average last spring frost is April 6 and the first fall frost is October 28, giving you a growing season of approximately 205 days.

At an elevation of 380 feet, Colbert County receives approximately 50.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 89°F, providing good warmth for Dahlias during the growing season. Clay soil retains moisture well for Dahlias, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Dahlias root diseases.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Colbert County, AL (Zone 8a) Long season
205 days
Last Spring Frost April 6
205 growing days
First Fall Frost October 28
Share this guide:

Colbert County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.2

Drainage

Well Drained

Dahlias Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 7 Transplant: Mar 28 🌸 Bloom: Jun 6 – Nov 7
Recommended (50%) ✗ May not fit
Start indoors: Mar 16 Transplant: Apr 6 🌸 Bloom: Jun 15 – Nov 16
Safe Start (90%) ✗ May not fit
Start indoors: Mar 28 Transplant: Apr 18 🌸 Bloom: Jun 27 – Nov 28

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 Colbert County

How your county's soil matches Dahlias's growing requirements.

Soil pH

Your soil pH (5.5–6.2) is more acidic than Dahlias prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The clay loam soil in Colbert County is excellent for Dahlias — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Dahlias.

How to Plant Dahlias

5"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Dahlias

3
successive plantings in your 205-day season

Sow every 8 weeks. Last sowing by Jun 30 to harvest before frost.

Dahlias Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Dahlias

Dahlias needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Dahlias Needs Rainfall You Supplement Action
Jan 4.2" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 4.8" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 5.1" 0" ✅ Rainfall sufficient
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.7" 0.6" 💧 Light watering
Nov 4.2" 0" ❄️ Dormant
Dec 4.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Colbert County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Dahlias 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.

Dahlias needs ~1,591 GDD — county provides 3,433 GDD Excellent fit

Dahlias Planting Timeline — Colbert County, AL

Dahlias Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow April 6 Apr 6 – Apr 27
Bloom June 15 Jun 15 – Nov 16

Plant 5" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November Bloom
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

205 days in Colbert County

Growing Tips for Dahlias in Colbert County

Direct sow Dahlias outdoors after April 06 in Colbert County when soil has warmed and frost danger has passed.

With Colbert County's clay soil (34% clay), work in 3-4 inches of compost before planting Dahlias. Avoid tilling when soil is wet to prevent compaction.

Common pests for Dahlias in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant tubers after all danger of frost has passed and soil temperature reaches 60°F — typically 1–2 weeks after last frost in most zones. Lay tubers horizontally 4–6 inches deep with the eye (growth point) facing up. Do not water until sprouts emerge; wet soil rots dormant tubers. Stake tall varieties (over 3 feet) at planting time to avoid root disturbance later. Pinch growing tips at 12–16 inches to encourage branching and more blooms. Deadhead regularly to extend the blooming season. In zones 8b and warmer, tubers can overwinter in the ground with a layer of mulch. In zones 3–8a, lift tubers after the first killing frost, cure for a week, and store in slightly damp vermiculite or peat at 40–50°F until spring. Divide tubers every year or two; each division must have an eye (bud) to grow.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Dahlias in Colbert County, AL?

Colbert County is in Zone 8a with an average last frost of April 6. Plan your Dahlias planting based on this frost date — see the calendar above for exact timing.

What planting zone is Colbert County, AL?

Colbert County, Alabama is in USDA Hardiness Zone 8a. The average last spring frost is April 6 and first fall frost is October 28.

When should I plant Dahlias in Colbert County County, ?

In Colbert County County, , plant Dahlias after the last frost (around April 6) and before the first frost (around October 28). Best results when soil holds above 50°F.

What growing zone is Colbert County County, for Dahlias?

Colbert County County sits in USDA Zone 8a. Dahlias grows reliably in zones 3a through 10b, so it's a good fit here.

Can Dahlias grow in Colbert County County's climate?

Yes — Dahlias grows well in Colbert County County's temperate climate. Colbert County County averages a 205-day frost-free season, with last frost around April 6 and first frost around October 28.

🌱

Your Colbert County Garden Planner — Free

A 22-page printable planner built for Colbert 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Colbert County, AL. 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.