The right watering techniques, soil, and light exposure will give you abundant blooms from midsummer until fall.
Dahlias make excellent cut flowers and can play the role of a thriller or filler plant in your container.
Their foliage provides a welcome architectural structure in a mixed planting in a large pot.
The Spruce / Adrienne Legault
Read on to learn about growing dahlias in pots, plus tips for planting, care, and more.
Use a pot with plenty of drainage holes in the bottom.
Ideally, the soil temperature should be at least 60F.
The Spruce / Adrienne Legault
Use shop lights fitted with one cool and one warm fluorescent bulb or grow lights designed for plants.
Plant taller varieties in heavy pots to keep a stiff wind from blowing them over.
Position tubers in the soil with the stem end facing up.
The Spruce / Kerry Michaels
Cover with soil so the top of the stem end is just barely below the soil line.
check that that the potting mix surrounds all the parts of the tuber without any air pockets.
How to Care for Dahlias in Pots
Water
Water immediately afterplanting dahlia tubersin containers.
The Spruce / Adrienne Legault
After that, wait to water them until you see green growth above the soil surface.
Watering too much before your dahlias have developed their root system can cause tubers to rot.
Check soil moisture regularly to keep the soil from drying out completely.
Light
Dahlias like full sun, though they don’t thrive in excessive heat.
Keep your potted dahlias in a spot that gets at least 6 hours of direct sunlight per day.
Add stakes at or shortly after planting.
Tomato cages can even work in a pinch.
You may need more than one stake per plant, especially if using bamboo poles.
Pruning
Pinch the tips off of dahlias when plants reach about 16 inches tall.
Remove the growth at the very end of the stem, just above a set of healthy leaves.
This will encourage multiple new stems grow in place of the pinched central stem.
Deadheading
For more flowers and fuller blooms,deadheaddahlias regularly after they die back.
Many nurseries also sell dahlias already started in containers.
Dahlias come in a huge range of flower sizes as well as plant sizes.
If you are looking for verylarge flowers, look for"dinner plate"dahlias.
If you are looking for shorter plants look for miniatures, or “low-growing” dahlias.
Short, dwarf, and compactdahlia varietiesare best for growing in pots.
Use a seed starting potting mix and seed trays with drainage.
Keep the plants in a warm place or use a heat mat during germination.
Beginhardening offdahlia seedlings a few weeks before your last frost date.
Wait to transplant seedlings outdoors until the soil temperature is at least 60F.
Dahlias require full sun to thrive.
If the tubers are properly overwintered, they can last a couple of seasons or more.
You do not need to water the pot, just let the tubers stay dry as they are dormant.
