pink and white petunia

How Many Petunias Per Hanging Basket: The Facts

Container gardening is all the rage. You can liven up walls, fences and gates with beautiful trailing foliage and stunning blooms. And if you plan to add hanging baskets to your garden display this year, you can’t go wrong with petunias. These cheery garden favourites are available in a dazzling array of colours, sizes and forms. But how many petunias per hanging basket?

We’ll cover everything you need to know about these fantastic flowers. Which varieties thrive in hanging baskets, caring and spacing of your plants, and how long you can expect them to live.

Can you put petunias in a hanging basket?

Yes, of course you can! In fact, planting and maintaining petunias in hanging baskets couldn’t be easier.

Be sure to choose a sturdy container with at least one drainage hole.

A large variety of pre-cut plastic, polypropylene or wire baskets are available at your local garden center.

Take a look at these great hanging baskets:

Wire Hanging Plant Basket with Coco Coir Liner 14 inch Round with Hanging Chain

Recycled Plastic Large Hanging Planter with Drain Holes 13.2 Inches Diameter

Wire Baskets

If you plan to use a wire hanging basket, you should fill it with a pre-cut liner or a plastic sheet to help keep the soil in place.

Cut a series of 2” slits around the basket so that trailing plants can come through.

Never use garden soil in your hanging baskets! It is too heavy to drain properly and can quickly become compacted. Instead, add a potting mix containing moisture-control granules (such as perlite or vermiculite) and slow-release fertilizer to a bed of compost.

This will feed your plants throughout the growing season and prevent the soil from drying out too quickly after watering. This mixture should be level with the slits around the side of the basket.

It’s best to poke your trailing plants out through the slits while wrapped in plastic to protect the young shoots. The root ball should sit on the soil surface with the leaves on the outside of the basket.

Tease out the roots and cover them with another layer of your soil mixture – stop about 2 inches from the rim of the basket. You can plant more trailing varieties around the rim – try positioning them between the lower plants for a balanced look. And then fill it the center of the basket with an upright variety or a nice grass for contrast.

Your new hanging basket of petunias will provide you with a bounty of colorful blooms from early summer straight to the first frost – that is, if you take care of it properly.

Feeding and Watering

Feeding and watering are both critical when it comes to caring for petunias in a hanging basket. In the limited space, the roots must have a steady access to moisture and fertilizer.

Sufficient sunlight is also important when growing petunias: your plants will need at least five to six hours of sunlight, but they will perform even better if they are located in full sunlight all day long. 

In fact, the more shade they are in, the less blooms they will produce.  So, if you’ve hung your basket under a porch or awning, be sure to rotate it weekly so the dark side can get some sun.

How many petunias per hanging basket?

There is a delicate balance to strike: while you want a lovely display, it’s important to avoid overcrowding your plants. With limited space for roots and resources, a good rule of thumb is to use one plant per inch of basket diameter – so 12 plants would fit in a 12-inch basket.

If you go with a larger trailing plant, such as Surfinia Petunias or choose a Grandiflora as the crown of your basket, then you may find that as little as 5-6 plants is enough to fill the basket nicely.

What are the best petunias for a hanging basket?

Grandiflora petunia purple flowers
Grandiflora Petunias are beautiful, striking flowers.

There are four main types of petunia plants: Grandiflora, Multiflora, Milliflora and Spreading (Wave). While the size and shape of the blossoms are usually particular to their type, each type of petunia comes in a range of colors. See examples of each below:

Grandiflora Petunias

Multiflora Petunias

Milliflora Petunias

Wave Petunias

You will find an enormous variety of petunias at most garden centres: fragrant, single or double blooms, ruffled or smooth petals in striped, veined or solid colors, with either mounding or cascading habits.

Most of the petunias sold today are actually hybrids which have been developed for specific design purposes, such as cascading over the edges of your hanging baskets.

Grandiflora types have the largest blossoms at nearly 5” in diameter; multiflora have smaller versions of the same blooms, while milliflora are the smallest yet – in terms of plant size and blossom diameter.

The newer Spreading, or Wave petunias, have blooms about 2” in diameter. The plants will typically spread 2 to 4 feet over a growing season, so they look great in containers. They tolerate heat and drought fairly well and generally require no deadheading.

Cascadia and Surfinia are two of the more popular types of petunia hybrids. These usually have larger flowers like traditional petunias, but in vivid and often unusual colours with lots of interesting shading and veining.

They grow in trailing stems up to 18” long, and are covered with an abundance of blossoms. These hybrids are also easy to care for and are perfectly suited for hanging baskets and window boxes.

Calibrachoa (Million Bells or Superbells) are another plant that looks just like tiny petunias. They are becoming increasingly popular because of how well they do in hanging baskets.

With their tiny flowers covering the foliage, Calibrachoa hybrids share the best traits of hybrid petunias: they are long blooming, require no deadheading, and are tolerant to many types of weather. They also come in unusual petunia colors, such as gold and terra-cotta.

How long do petunias last in a hanging basket?

How long can you expect to enjoy these classic summer plants? There are actually 2 answers to that question.

If you’re asking how long the plants themselves actually live for, that varies depending on care and climate. Petunias can live for at least 2-3 months although they typically behave as annuals because they can’t abide freezing temperatures and don’t overwinter well.

If you want your outside petunias to live longer than a single season, you have to protect them from the cold by bringing them indoors. You can treat them like houseplants until the following spring and extending their lives by a year or two.

If you want to know how long the flowers last once your petunias bloom, that’s more difficult to determine.

It’s hard to set a timeline for each individual blossom but, while they’re not typically long-lived, the plants may put out so many of them that you may not really notice any blooms fading and dying.

So now that you know the facts about raising petunias in your hanging baskets, I have only one question for you: when do we start?