When to Plant Dahlias?

When to plant dahlias? A colorful start to summer

Why dahlias deserve a place in your garden

Dahlias aren't just any flowers. These colorful tubers provide an explosion of shapes, heights, and shades during the summer months. Whether you prefer tiny pompoms or giant burgundy ones, there's something for everyone. They bloom from July until the first frost, making them ideal for keeping your garden vibrant for months.

Dahlias are also excellent cut flowers. One plant often produces dozens of flowers, allowing you to cut them again and again. Don't want to plant them in the ground or don't have the space? No problem: they also thrive in large pots.

The best time to plant dahlias

Dahlias are frost-sensitive. Therefore, it's crucial to wait until the risk of frost has completely passed. In Belgium and the Netherlands, this means waiting until mid-May to plant them outdoors in the ground. Ideally, after the Ice Saints (around May 15th). Preferably choose a partly cloudy or rainy day to avoid planting stress.

Want to enjoy flowers sooner? You can also start growing dahlias starting in March or April in a greenhouse or indoors in a bright spot. Use a pot with good potting soil, such as those found in our potting soil and accessories category. This way, the tubers can start growing and will be ready for planting out as soon as the weather warms up.

How to plant dahlias in the open ground

Choose a sunny spot in the garden with well-drained soil. Enrich the soil if necessary with organic matter, such as compost or coconut fiber like our coconut bark . Dig a planting hole about 10 to 15 cm deep for each tuber.

Place the tuber in the hole with the growing tips facing up. Cover gently with soil, but don't press too firmly. Then water well. Keep the soil slightly moist, but don't allow standing water, as dahlias don't like wet feet.

Planting dahlias in a greenhouse or pot

Want to get a head start, or do you have a city garden? You can start in March or April in a greenhouse or pots. Choose a large pot with drainage holes and use airy soil, perhaps enriched with perlite for good drainage.

Plant the tuber as you would in the ground. Place the pot in a bright, frost-free spot. When it's warm enough outside, you can harden off the plant (gradually acclimate it to the outdoors) and transplant it to the garden. Or simply leave it outside on the patio or balcony.

Tips for successful flowering

Protection against snails and cold

As soon as your young shoots emerge from the ground, they're a favorite of snails. They can suddenly disappear, especially after rainy weather. Protect your young plants with snail rings or ecological snail pellets.

Also, keep an eye out for cold nights in late May or early June. If the temperature suddenly drops, it's best to temporarily cover the plant with fleece or a pot to prevent damage.

Support and maintenance during the season

Some dahlia varieties can grow quite large. Taller varieties often bloom on long stems that are sensitive to wind. Therefore, provide support in time, for example, with a stake or trellis.

Water regularly on warm days and remove spent flowers. This will prolong flowering and keep the plant looking neat. Use liquid fertilizer for flowering plants once every two weeks, and you'll be rewarded with even more buds.

Store your tubers in winter

Dahlias are not winter-hardy. So, dig up the tubers before the first frost. Do this on a dry, sunny day. Shake off the excess soil and let them dry for a few days.

Store the dried tubers in an airy, frost-free place. A wooden crate lined with newspaper or sawdust works well. This way, you can enjoy your favorite flowers again next year.

Combine with other bloomers

Dahlias are beautiful eye-catchers, but they also combine beautifully with perennials or ornamental grasses. Consider Aglaonemas as a houseplant alternative, or plant them in your flower border alongside Calatheas for a lush, potted look.

Love plants and want to give your interior a tropical look? Then consider the rare Alocasia Zebrina or the popular Monstera Minima . Not for outdoor use, but perfect for keeping the plant bug alive year-round.

Looking for more garden planning inspiration?

Want to know when to plant other tubers and flowers? Then be sure to check out our guide on when to plant flower bulbs or the tips on when to plant flowers in the garden .

Find more plant love on our plant blog , or visit our store in Leuven and discover everything you need to turn your garden or balcony into a summer flower festival.