Petunia Container Care: Growing Petunias In Pots

Petunia Container Care: Growing Petunias In Pots

By: Liz Baessler

Planting petunias in containers is a fantastic way to showcase them. Whether in hanging baskets or containers on tables or a front porch, growing petunias in pots brings vibrant color throughout the summer to whatever area you choose. Keep reading to learn how to grow petunias in containers.

Caring for Petunias in Pots

Petunia container care is very easy. Soil in containers is prone to heating up and drying out much faster than soil in the garden, but petunias are particularly hot and dry hardy. This doesn’t mean you should neglect your petunias, but you should allow the soil to dry out completely between waterings.

Every few days, give them a long, slow drink. Wetting the flowers and foliage can promote disease, so water either from below or close to the surface of the soil. You don’t want to waterlog your roots either, though, so make sure your container has very good drainage.

Petunias are heavy feeders. Apply a slow release fertilizer at the time of planting, then follow up with a liquid fertilizer every week or two throughout the season.

Place your containers where they will receive full sun – six hours per day is good but eight is preferable for the fullest possible blooms.

How to Grow Petunias in Containers

You can purchase special trailing petunias, which will perform dramatically in containers. However, growing petunias in pots, regardless of their type, should not disappoint you, as long as you treat them right.

When planting petunias in containers, be sure not to crowd your plants, limiting yourself to three per 12-inch (30 cm.) pot.

If your petunias start to flag or grow leggy, cut them back and fertilize them. They should branch out with vigor. Cut flowers for bouquets frequently to encourage new growth and remove dead flower heads as soon as they appear.

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Everything You Need to Know About Container Gardening

Pots, tubs, and half barrels overflowing with flowers add appeal to any garden, but container gardening can serve a practical purpose too. Container gardening is ideal for those with little or no garden space. In addition to growing flowers, gardeners limited to a balcony, small yard, or only a patch of sun on their driveway can produce a wide variety of vegetable crops in containers. Basil, chives , thyme, and other herbs also are quite happy growing in pots, which can be set in a convenient spot right outside the kitchen door.

Container gardening also adds versatility to gardens large and small. Plants lend instant color, provide a focal point in the garden, or tie in the architecture of the house to the garden. Place them on the ground or on a pedestal, mount them on a windowsill, or hang them from your porch. A pair of matching containers on either side of the front walk serves as a welcoming decoration, while container gardening on a deck or patio can add color and ambiance to such outdoor sitting areas.

You can use single, large containers for outdoor decoration, but also consider arranging groups of pots, both small and large, on stairways, terraces, or anywhere in the garden. Clusters of pots can contain a collection of favorite plants — hen-and-chicks or herbs used both for ornament and for cooking, for example — or they may feature annuals, dwarf evergreens, perennials, or any other plants you'd like to try. Houseplants summering outdoors in the shade also make a handsome addition to container gardening. Window boxes and hanging baskets offer even more ways to add instant color and appeal.

Containers planted with a single species — rosemary or a bold variegated ornamental grass, for example — can be stunning garden accents. Containers planted with a mix of plants are fun to create and offer almost unlimited possibilities of combinations. The best combinations depend on plants that feature handsome foliage and flowers produced over a long bloom season.

One easy guideline for choosing the plants to combine in a container is to include "a thriller, a spiller, and a filler." That translates to at least one focal-point plant (the thriller), such as coleus or a geranium with multicolored leaves, for example, combined with several plants that spill over the edge of the pots — such as petunias, bacopa, creeping zinnias, or ornamental sweet potatoes. Finally, add the fillers, which are plants with smaller leaves and flowers that add color and fill in the arrangement all season long. Good fillers include salvias, verbenas, ornamental peppers, and wax begonias, as well as foliage plants like parsley or licorice plants. You may also want to include a plant for height, such as purple fountain grass. Add a trellis or pillar to a container and you can use a vine to add height to the composition. You'll need a total of five or six plants for an 18- or 24-inch container, for example.

Site and soil

Petunias need at least 5 or 6 hours of good sunlight they'll perform even better when located in full sun all day.

The more shade they receive, the fewer flowers they'll produce.

Impatiens are a better choice for blooming in shady places.

While soil needn't be terribly rich to grow good petunias, it must drain decently.

It's always useful to improve garden soil by conditioning it with organic matter, such as peat moss, compost or manure.

Spread the organic matter 2 to 3 inches thick.

Incorporate it into the soil to a depth of 8 to 10 inches, using a rototiller or garden fork.

Helps open up heavy clay soil, which improves drainage, but can also increase the ability of light, sandy soil to hold moisture and nutrients.

Why do I need a pick

Many beginner gardeners often ask: "Why, when and how to dive petunias?" Let's start with its first part. No matter how careful you are when planting, no matter how carefully you monitor your crops, they are most often obtained either thickened or too rare. Too thick shoots must definitely be planted, otherwise the plants will turn out stunted and may not bloom. And those between whom there is sufficient distance feel better in separate containers, form powerful roots and strengthen their trunk. The answer to the second question - about the timing - different gardeners give different. Some tend to dive after the appearance of the 5-6th leaf. Others call earlier dates - 2-3 leaves.

Before diving petunias, they need to be shed well. Transplanting sprouts is cheaper and more convenient in disposable cups filled with appropriate soil, with holes in the bottom. But if financial circumstances allow, buy special peat, as diving petunias and transplanting them to a permanent place in such tanks is much more convenient. When using a simpler container in a poured earth, a shallow hole is made and irrigated with water. With a spatula or knife, one plantlet is carefully removed and moved into a glass. On top, the roots are sprinkled with soil.

How to Grow Petunias

Bedding Petunias are annual plants lasting just the one summer season. They cannot be over-wintered or in any way saved as plants for the following year. Some types of trailing petunias Surfina varieties for instance can be treated as perennials with late summer cuttings taken to be over-wintered in a warm greenhouse.

There are several methods of growing petunias. Simply choose the best growing method that fits in with your level of expertise and time allowance.

Most petunias are bought as young plants from garden centers or nurseries either as a few plants in a bedding plant strip, or as small patted plants often showing the first bell flower as a good selling point. This also help you in choice of colour, for the colour range of petunias encompasses white through to deep red and all the pink shades between delicate mauve to deepest purple with oranges and yellows also thrown in to give you maximum colour choice.

The young plant purchase method is for those who want an instant splash of colour. Most garden and window box petunia flowers start life this way.

Plug Plant Petunias

Petunias can also be bought as small seedling plants in plug units. Depending upon size, these can either be planted out or placed in window boxes, patio pots or hanging baskets, where they will soon multiply in size and produce flowers within a few weeks. It is sometimes necessary to pot into larger pots if the weather is not quite right for planting out. This takes a little time, added materials an of course suitable growing space and conditions.

How to grow Petunias from Seeds

Petunia seeds germinate quite easily and do not need a high temperature. If growing petunia seeds in a heated propagator, carefully gauge the temperature to mid range - 70-75 degrees F - 21-23 degrees C maximum. Once germinated grow cooler or plants will become leggy!

Aim for cool growing conditions and a nice compact bushy petunia seedling. Flowering time from seed sowing in ideal conditions is 12 - 14 weeks. Thats more than three months of total care! Do you have time and space?

How to Plant Petunias

Do NOT plant Petunias outside until all frosts have gone - late is better than early! Make sure the plants are properly hardened off.

Location is important for Petunias. In the garden beds and borders, the sunniest position with moist soil conditions is ideal. Not easy to combine both situations so dont worry too much. Petunias are happy in dry areas once established. They will simply need watering for a few weeks after planting to ensure that they get settled in without too much stress. After that, watering only in the driest conditions is necessary.

You will be planting small plants but do not make the common mistake of planting too close together. Most petunias are best planted a minimum of 9in apart (20cm) and will soon grow to cover up any bare soil between. Good spacing of your petunias also ensures compact plants rather than untidy, unproductive spindles of shoots. Planting Bedding Plants

Did the hole slightly bigger than the plant pot or plug plant. Insert the petunia and firm into position with a bit of fine or sifted soil. Give plant of water which will settle the soil nicely around your new petunia plant.

Planting petunias in hanging baskets is much the same and is covered fully in this separate article about growing petunias in hanging baskets.

Caring for Petunias

Petunias have shallow root systems. This means that they will lose hydration more quickly than other plants. Make sure to water your petunias on a regular basis. Don’t make the soil too soggy, though. Excessive water in the soil can lead to yellowing of the foliage and root rot.

If you have petunias in containers, you will need to water more frequently. Daily watering may be necessary, especially in the heat of summer. To have beautifully blooming petunias all summer, feed them with a liquid fertilizer monthly. Alternatively, you could use a slow-release granular fertilizer when you plant the flowers.

If you have your petunias in containers, you will probably need to fertilize them more often. That is because the nutrients can more easily end up washed out.

How to Prune Petunia Branches

Not only do you need to deadhead your petunias, but you must also prune their branches. If you don’t do this, you will end up with leggy petunias. A leggy petunia plant is one with stems that are too long and lanky, detracting from its floral beauty.

To keep your petunia plants properly pruned, cut back a few of the stems (or branches) each week. You should begin this early in the season. Sometimes it will be necessary to cut long stems that have flowers on them, even if you like the way the flowers look.

Always cut off petunia stems that are eight inches long. When cutting back your petunias each week, cut three or four of the stems in half. Ensure you cut above each node. You will find that the petunia plant produces new growing tips beneath each place you cut.

Correct and regular pruning of your petunia plant’s stems or branches will make your petunia plant fuller and more attractive.

Grow Your Petunias as Perennials

Petunias are most often used as annuals because they are too delicate to be perineal in most climates. However, there are ways you can make your petunia plants last for two or even three years.

The key is to make sure that your petunia plants are protected from cold weather. If they aren’t, they won’t grow back as healthy plants the next growing season. To protect your petunias from cold winter weather, dig them up and put them into containers. You can then bring them indoors and put them in a covered space such as a sunroom or garage.

In the winter, your petunias will look like a green houseplant. When you put them outdoors again in the spring, they will begin to bloom.

Petunia Care


Petunias can take summer heat in even the warmest regions, but you'll need to water plants consistently to keep the flowers coming. In landscape plantings, water spreading petunias, such as Wave or Supertunia types, a few times a week once summer heat arrives. These plants can grow up to a foot a day in ideal conditions, and they need sufficient water to fuel that intense growth.

Other petunias can get by with less frequent watering — maybe twice a week in southern areas and weekly in cooler northern zones.


Spreading petunias have humongous appetites. Feed them weekly in planting beds and pots with water soluble fertilizer. Fish emulsion is a good natural choice. In containers, try a bloom booster fertilizer. Look up your specific petunia type online to learn if you need to remove spent flowers. With many of the newer petunias, plants are self-cleaning.


If petunia plants start looking a little ratty in midsummer, give them a trim. Remove up to 20% of total growth — either in length or number of stems. Fertilize plants after trimming to jump-start new growth. Depending on where you live, you might need to repeat the process in late August, especially if petunias usually grow well into fall in your region.