Why Dahlias?
If you're going to grow one flower in your garden this year, grow dahlias. No other flower gives you this return: months of continuous bloom, dozens of flowers per plant, every color imaginable (except true blue), and an almost theatrical range of forms — from tiny pompoms to dinner-plate blooms the size of your face.
We grow over 50 varieties on the farm. First-time growers always ask us which ones to start with. Our answer: any of them. Dahlias are more forgiving than their reputation suggests. The rules are simple. Follow them and you'll have flowers.
What You Need to Know About Tubers
Dahlias grow from tubers — fleshy, potato-like root structures that store energy for the plant. Each tuber needs at least one "eye" (a growth point, similar to a potato eye) to sprout. When you buy tubers from us, we've already divided them to ensure each one is viable.
Store tubers properly before planting: Keep them in a cool (45–55°F), dark, slightly humid spot — a basement or root cellar is ideal. Do not freeze them. Do not let them dry out completely. A cardboard box with slightly damp peat moss works perfectly.
When to Plant
In Georgia (Zone 7b–8a), plant after your last frost date and when soil temperatures are consistently above 60°F. For most of the Atlanta metro area, that means mid-April through early May.
A simple test: stand barefoot on the soil. If it feels comfortable, it's warm enough for dahlias. If it feels cold, wait.
Planting too early in cold, wet soil is the number one cause of tuber rot. Two weeks of patience now saves the whole planting.
How to Plant
- Choose a full-sun spot — 6–8 hours of direct sunlight minimum. Dahlias in partial shade produce weak stems and fewer flowers.
- Amend the soil — Work 2–3 inches of compost into the top 12 inches. Add a balanced fertilizer (10-10-10) and a handful of bone meal per hole.
- Dig a hole 6 inches deep — Lay the tuber horizontally with the eye facing up. Cover with soil.
- Do not water at planting. This is the most counterintuitive instruction and the most important one. The tuber has stored moisture and energy to begin growing. Watering a dormant tuber in cool soil causes rot. Wait until you see green growth above the soil — usually 2–3 weeks — then begin regular watering.
- Space plants 18–24 inches apart for standard varieties, 12–15 inches for smaller types.
- Install stakes at planting time — not after the plant is 4 feet tall and falling over. A 5-foot bamboo stake or metal T-post driven in at planting prevents damage to tubers later.
The Pinching Secret
When your dahlia reaches about 12 inches tall with 3–4 sets of leaves, pinch out the center growing tip. Remove the top 3–4 inches of the main stem.
This feels wrong. You're cutting a healthy plant. Do it anyway. Pinching causes the plant to branch, producing 3–4× more flowering stems than an unpinched plant. Every commercial dahlia grower pinches. It's not optional — it's the difference between a plant and a flower factory.
Watering and Feeding
Once dahlias are actively growing, they want deep, infrequent watering — 1–2 inches per week, delivered slowly so it soaks in rather than running off. Drip irrigation is ideal. Overhead watering promotes powdery mildew; keep foliage dry when possible.
In July, switch from a balanced fertilizer to one higher in phosphorus and potassium (like 5-10-10). This shifts the plant's energy from leaf growth to flower production.
When to Cut
Cut dahlias when blooms are 75% open. They don't continue opening after cutting, so timing matters. Harvest in the morning or evening (not midday heat), and immediately place stems in cool water.
The more you cut, the more dahlias bloom. Regular harvesting signals the plant to keep producing. Leave flowers on the plant past their peak and production slows down. Pick every 2–3 days during peak season.
At the End of the Season
After the first killing frost, the dahlia foliage will blacken. Wait a week, then dig the clumps before the ground freezes hard. Let them cure in a dry spot for a few days, then divide (each division needs at least one eye) and store for next spring.
Many gardeners in Zone 7b/8a successfully overwinter dahlias in the ground with heavy mulching. We recommend digging your first year until you know how your specific spot drains — wet winters kill more overwintered tubers than cold temperatures.
Dahlias are the one flower that rewards you for being greedy. The more you pick, the more they give.
We sell dahlia tubers from our own fields — the same varieties we grow for market and weddings. Browse the seed and tuber shop for what's available this season. Questions? We're happy to help you pick the right varieties for your garden and goals.