Petunias: Planting, Growing, And Caring For Them

You can beautify your garden even more by planting petunias!

That is if you can properly care for them.

It’s the worst to watch helplessly as your plants wither away no matter what you seem to do.

Nobody should feel this way about their plants.

You don’t have to.

Purple, white, pink, and red petunias

We get questions about petunias a lot more frequently than you would think, mostly on how to bring them back to life.

A lot of the time we are able to help!

But sometimes, it’s simply too late to do anything besides replant next year.

We don’t think anyone should go through this.

You can watch your petunias blossom through the years by following this guide on planting, growing, and caring for them.

Let’s start with why gardeners love them so much.

You can create your dream yard with these plants from our garden center >>

A Little Bit About Petunias

Gardeners and people in general love petunias because of their beauty and versatility.

They can be used in:

  • Flower beds
  • Hanging baskets
  • Window boxes
  • Other types of containers

You can also buy them as cut flowers to give to someone special.

Their blossoms come in many colors like pink, white, blue, and even multicolor.

The petals are either straight or ruffled.

You may want to choose from the two main types below.

2 Main Types Of Petunias

Grandiflora

If you like larger flowers you’ll love Grandiflora petunias.

They are known for having fewer, but larger, showy flowers.

A number of Grandifloras are cascade selections, which are great for growing in hanging baskets and window boxes.

Purple Grandiflora petunias

Multiflora

These are the cute little blossom flowers.

Multiflora petunias grow closer together and have smaller but more numerous blossoms.

This makes them generally better at withstanding harder winds and rains than Grandifloras.

They are best for summer garden beds or in a border mixed with other plants.

Pink and white Multiflora petunias

Both Grandiflora and Multiflora types may have single flowers, with one set of petals on each flower, or double flowers with multiple sets of petals on each flower

Planting Petunias

You want the best for your petunias, right?

Planting them in an area where they can best grow will get you the best results. As for where to plant petunias, areas that stay sunny all day are best. They can be in the shade a few hours a day, but they may not bloom as well. Plant them in light and easy draining soil.

Planting white petunias in a flower bed
Photo by Larry Jacobsen – creative commons license 2.0

Planting Petunias From Seeds

Starting them indoors for 10-12 weeks can help make sure they actually grow.

They like to be kept in warm places until they start germinating.

After that, move them to a cooler, yet sunny, area and water them.

You’ll know they are ready to go outside when they have at least 3 leaves on the stem.

Planting Petunia Transplants

Wait until after the last spring frost to plant.

Plant them about 1′ apart.

You’ll want to spread two pounds of 5-10-5 fertilizer or one pound of 10-10-10 dry fertilizer per 100 square feet during planting.

A half rate application can be spread around the plants in July if needed

But be careful with that fertilizer!

Planting purple petunias in a container
Photo by Jenni Sweat, slightly cropped and made smaller – creative commons license 2.0

How To Care For Your Petunias

Soil Condition

You don’t want to use too much fertilizer.

Too much fertilizer can cause more stems and fewer flowers, which nobody wants.

In high pH soils (alkaline soils) additional iron or iron sulfate may help lessen chlorosis (yellowing).

Watering Your Petunias

You only need to water them about once per week.

If they stay dry for too long, such as during a drought, water them 2-3 times per week.

Now, while your petunias like water, they don’t like to be too wet.

If the soil around the plants remains excessively wet for several days, they can contract chlorotic growth or disease.

This means they won’t grow as beautifully as they can.

You can help with this by pruning them.

Pruning Your Petunias

You can help your petunias bloom longer and better.

But it will mean snipping parts of the plant.

Caring for window box flowers

“Pinching” the plants can be used to increase the number of flowering stems and discourage too many leaves.

This is done by using your fingers to pinch off new stems.

You’ll also want to deadhead your petunias.

Removing old flowers (dead heads) when they start to fade encourages repeat blooming.

You’re helping the whole plant be healthier and look better.

Adding Mulch

Your plants will all love you if you add mulch around them:

  • Lower their soil water evaporation
  • Reduce splashing of water onto the lower leaves
  • Moderate soil temperatures
  • Reduce weed competition

Speaking of weeds, removing them is also good for your garden in general.

How Long Do Petunias Last?

Your petunias should start blooming during springtime and last into fall.

They will be at their best during the summer though (they do love to sunbathe).

In areas with more mild-mannered weather, they can even bloom into winter.

Most of the time, you will be replanting them every spring as they cannot survive most winters.

Pink petunias with a white rim

Protecting Your Petunias

They are normally easy to grow, but they may need your help every so often.

Protecting them from insects such as aphids comes with the job.

Aphids love petunias.

These little bugs crawl all over them and take out the nutrients. Just blast them off with a hose, but not too harshly or you may damage your petunias.

Other insects can appear as well, though they may not be too much of a problem.

Gray mold and soft rot can occur in rainy climates. Well, only if you don’t choose weather-resistant types.

As long as you look after them, petunias will bloom wonderfully.

Try Something New With Your Garden

These flowers are well worth the extra attention they need from time to time. They are also great for beginner growers as they are decently hardy.

But they aren’t the only flower out there.

You can see more amazing plants on our garden center page >>