How to Grow Dahlias In Containers

Dahlias are heat loving plants that grow best in warm soil. Growing these flowers in
containers is a great way to give them the extra warmth they need to put on a spectacular
show. Container gardens also make it easy to enjoy dahlia flowers almost anywhere
around your home. Decorative border dahlias have the blooming power of full size
dahlias, but with a compact size makes them a great choice for containers. This article will
familiarize you with what’s in your kit, how to plant them and how to care for them for the
best results.

What’s Included in Your Kit

Your kit includes a bag of soil, 1 dahlia tuber, the decorative pot, a lid and a small
plastic bag containing 3 rubber plugs.

Step 1: Save the Base Plugs

Your container comes with a bag containing three rubber plugs. Install the plugs when
starting your plants indoors or when moving inside to store for the winter. When the plugs
are removed for outdoor use, this provides adequate drainage for your soil. When indoors,
these plugs prevent a leaking mess.

To install, press firmly on the top of the plug until the wider top is flush against the
bottom of the pot.

Step 2: Arrange Bulbs & Soil

Fill the container with about 2/3 of the soil. Place your dahlia with the long
tubers (bottom) down and short stem (top) facing up.

Backfill the soil on top of the dahlia tuber. The tuber should be about 1” below the soil
surface.

Step 3: Watering Your Dahlias

Water lightly after planting until you see the sprouts above the soil level, usually about
once per week. Do not overwater as keeping the soil too wet will result in a rotting
tuber.

Soil should feel somewhere between “fresh out of the bag” and moist. Not saturated or
dry like sawdust. To check soil place a finger 1” below the soil’s surface to feel for
moisture. Once the dahlia has sprouted above the soil, water to keep the soil moist to
the touch or as often as you would any other container plants.

Step 4: After Care

Dahlias bloom best in full sun, so choose a sunny spot. Once your dahlias are 8-10" tall,
begin fertilizing them with an all-purpose liquid fertilizer every 3 to 4 weeks. To
promote plenty of blooms and strong plants you can use a technique for dahlias called
“Pinching”.

Step 5: The Value of Pinching Dahlias

Pinching or "topping" young dahlias will give you stronger, bushier plants with more
flowers. Pinching temporarily redirects the plant's energy toward producing stems and
leaves rather than buds. It will take an extra week or two to get flowers, but it's
definitely worth the wait.

When to Do It. The best time to pinch is when the plant is about 10" tall and has at
least 4 sets of leaves on the center stalk. At this stage it is growing rapidly and will
quickly recover from being pinched.

How to Do It. Locate the upper-most sprout on the main stem (see below) and snip it
off with your fingers or scissors. Take care not to tear the stem or damage the nearby
leaves. See the image below.

Why to Do It. Removing the plant's terminal bud will stimulate lateral buds (lower on
the stem) to develop into new stems. Where the sprout was removed, the plant will
generate two shoots rather than one.

Step 6: Controlling Insects and Disease

Aphids are a popular pest that likes to attack dahlias. Ladybugs, parasitic wasps, and
lacewings will all attack aphids, so avoiding chemical pesticides is beneficial to your
dahlias. Using a strong stream of cold water can help wash aphids off the plants.
Insecticidal soap can also help.

Removing spent blooms and keeping your dahlias clean is the best way to prevent any
diseases that would shorten your dahlia’s bloom-span.

Step 7: Deadhead Regularly

As mentioned above, removing spent blooms is a great way to prevent any dahlia
diseases, but deadheading also encourages new blooms to continue all the way up to
the first frost. Simply use your fingers or gardening scissors to clip off the flowers that
are browning or looking tired.