When to Plant Petunias – Planting Guide 2024

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One of the first signs of spring is when you can plant your petunias. Full of delightful colors, petunias are usually grown as an annual although in some areas they can actually thrive as a perennial. Learn when to plant petunias so that your spring will always be full of color.

When to plant petunias: Petunias are annual so you will need to plant them new each year. For seeds, start them indoors about 10 weeks before the last frost date in the spring. Then, you can transplant them outdoors. You can also skip the effort and simply purchase young petunia plants. These are readily available at most gardening centers. There are many types of petunias to purchase including some with large blooms, some with tiny blooms, and some that spread out across your garden. Petunias are perfect for garden borders. You can also plant them in containers or hanging baskets. They are easy to care for and will quickly add some personality to your garden. Consider making a colorful hanging basket for Mother’s Day or as an Easter gift. When you plant your petunias in mid-spring, they will continue to bloom until mid-summer, which is a nice, long growing season.

Planting Petunias in Different Climates

Tropical Climate

With a tropical climate, you may just have the right conditions to plant petunias as a perennial. If you live in hardiness zones 10 or 11, which means your winter temperatures are always above zero, you can try planting petunias and see if they will continue to grow each year.

Dry Climate

You should be able to plant petunias in a dry climate. These flowers need water, so you will have to add more, but they do not like their roots to be wet for a long time.

Temperate Climate

A temperate climate is great for petunias. The only thing you need to take into consideration is if you have very wet springs.

Petunias need soil that drains really well. If you have compacted soil or rain that is very heavy in the spring, you might want to consider planting your petunias in a container or basket. This way the water will be able to drain better.

Continental Climate

Petunias do very well in a continental climate. You may have to wait a bit longer before you can plant them as they can’t be in the ground before the threat of frost is over.

While you can try them from seed, because of the long winters, it is best to plant young petunias in this type of climate.

Polar Climate

Petunias definitely need sunshine and warmth to grow. A polar climate will not be able to sustain these flowers.

Choosing Petunias

When selecting your petunias, there are five categories to choose from.


These petunias have quite large flowers that make a bold statement. They are perfect for hanging baskets as too much water on their roots can cause damage.


Within this category are the more popular varieties of petunias as they are very hardy and have prolific blooms. They are fine with wet weather, so keep that in mind if you have a lot of rain in the spring.


For those that love petunias but want them on a smaller scale, check out this category. You should expect the flowers to be just 1.5 inches wide but they last quite a while.


You will find petunias in this category to have medium-sized flowers. There are many popular choices within this grouping.

Trailing Petunias

Perfect for groundcover, this category of petunias will continue to spread all season long, up to 3 or 4 feet. They are also perfect for hanging baskets.

How to Plant Petunias

Seeds vs plants

While you can plant petunia seeds, they can be difficult to find. This is because most people simply plant them when they are young.

Petunias are often planted as annuals, which means they only last for one season and you will then have to plant them again the following year. Sometimes, in very warm areas, such as hardiness zones 10 and 11, you can plant treat petunias as perennials.


Once you’ve decided you want a garden full of petunias, you should then think about the location. Petunias don’t grow very large, averaging about 6 to 18 inches in length.

Therefore, they are great for borders. You can also bunch them up for containers and even hanging baskets.

Petunias are perfect for your garden. You can also make really nice gift arrangements with them, and they are perfect for Mother’s Day or Easter.


Petunias grow best in the early spring. For those that want to start from seed, plant your petunias inside about 10 weeks before the last frost date of the spring. You can then transplant once the threat of frost is over.

Those that want less work can simply head to their local gardening store where you will find plenty of choices and colors. Plant young petunias in your garden after the last frost date, which is usually late April to early May.


Petunias do best in full sun. If they are in the shade, they can become spindly and their flowers will be very lackluster.


For soil, make sure you mix in some compost before planting. However, petunias don’t have very high needs so your regular garden soil should be fine.

Just make sure that the soil drains well. Petunias do not like having their roots perpetually wet, which can be a concern in rainy spring weather.

If you are planting young petunias, dig a hole that is slightly larger than the root structure. Gently place your plant inside so that the top of the root ball is at the same level as your soil.

Fill in the hole with soil and then tamp it down to encourage the roots to take hold.

How to Water Petunias

Although you should give your petunias a good watering after you first plant them outside, after that they do not need a lot of attention.

Aim to water your petunias about once a week. However, if you have a drought period, then be sure to increase your watering schedule.

Water for long periods of time. This will encourage the roots to grow deeper, making them more stable and healthier.

The only factor to consider is if you have your petunias in a hanging basket or container. If this is the case, then you will need to add more water each week.

How to Grow Petunias


Petunias will continue to bloom throughout the season, which is mid-spring to early summer. To encourage bold colors, add fertilizer once a month.

Use a liquid fertilizer that will penetrate into the ground and reach the roots. A standard 10-10-10 fertilizer should be fine for this plant.


Because petunias have such a long growing season, you will want to tend to them throughout the spring. As summer approaches, the petunia plants can start to become leggy, which is when the stems are long and the flowers are only at the very end.

To counteract this, you can prune the shoots back. Cut them to half their length and as a result, more branches will form and thus more flowers.


As petunia flowers start to fade, you can encourage new blooms by deadheading your plants. Simply clip off the faded or dead blossoms.

This will encourage new growth as less energy will go towards the seed pods inside the dead blossoms.

Keep roots dry

Overall, petunias are easy to care for. The one thing you want to watch out for is oversaturating the soil.

Too much water on the foliage of petunias can also lead to diseases. When watering, always try to water the soil and not the entire plant.

Annual growth

Unless you live in a very warm climate where the lowest temperatures are still above freezing, petunias need to be treated as an annual. Thus, you will need to dig them out of your garden once their growing season is over.

Wait until the last blooms are over before digging them up. This should be an easy process and you can always dispose of any remnants in your compost bin.

Even though you will have to spend money each year if you want fresh petunias, they do have a long growing season. Thus, they are a decent investment.

How long do petunias take to grow?

Petunias should be planted in the spring as long as there is no more threat of frost. Then, they will bloom through mid-spring into summer.

If you start with seeds, then they should be planted indoors 10 weeks before the threat of frost is over. However, if you purchase young petunia plants from a nursery, some may already be blooming when you plant them.


Petunias are annual but when you plant them in the spring, they will last all season until summer. Full of gorgeous color, petunias are an easy way to brighten up spring.

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