Dahlia Growing Guide
Dahlia is a great next step in your growing journey. Follow this guide from planting to harvest and you'll do great.
At a Glance
Difficulty
Moderate
Category
Flower
Sun Exposure
Full Sun
Frost Tolerance
Frost Tender
Cold Hardiness
Survives to -1°C
Plant Family
Asteraceae
Growing Season
Warm Season
Plant Lifecycle
Perennial
Also grows well as
How to Start It
★ Recommended for beginners
Plant a tuber on its side about 10–15cm deep after the last frost, eye/sprout pointing up. Don't water much until shoots appear (wet dormant tubers rot).
The cutting garden's superstar: dahlias bloom non-stop from midsummer until the first frost, in every colour and form. They grow from frost-tender tubers planted in spring after frost. Three jobs unlock their potential: PINCH the growing tip early to make them bushy, STAKE the tall ones, and DEADHEAD relentlessly — the more you cut, the more they flower. In cold climates, lift and store the tubers over winter; in mild ones, mulch and leave them.
When To Start
First Chance to Plant
—
Last Chance to Plant
—
When should you plant Dahlia?
Your planting dates depend on your local climate. Sign up and add your location to unlock personalized dates.
Your Dahlia Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
The Journey Ahead
Dahlia's Lifecycle
Seedling
Mature Plant
Seed Production
Step 2
Planting & Sprouting
Growing Tips
- 1Full sun, rich soil, and steady summer water grow great dahlias.
- 2Pinch out the tip above the third or fourth leaf pair when young for a bushier, more productive plant, and stake the tall varieties at planting so you don't spear the tubers later.
- 3Deadhead or cut often.
- 4The main winter task in cold zones is lifting and storing tubers; watch for slugs on emerging shoots and earwigs in the blooms.
Seedling Phase
Step 3
Growth & Maturity
120 cm
Mature Height
60 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
When to Pick
Blooms midsummer to first frost; the more you cut, the more it flowers
How to Harvest
- 1Cut dahlias in the cool of the morning when the flower is fully or almost fully open (unlike many flowers, the buds barely open further once cut) and plunge the stems straight into water.
- 2Deadhead spent flowers constantly — a faded bloom looks like a pointed bud, a new one is rounder.
- 3After the first frost blackens the foliage in cold climates, lift, dry and store the tubers somewhere cool and frost-free.
Step 5
Saving Seeds
Seed Production
Ready to grow this?
Get started with Limitless Growth.
Save this guide, see exactly when to plant dahlia where you grow, and start the 5-step course we wrote for first-time growers.
Get started →
